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" Apply the principle m of science, and make them available to the needs, 
the comforts, ami luxuries of life." — Tyndall. 





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Brighton: 129, north street. 

New York: E. & J. B. YOUNG A CO. 


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London & Bungay. 


We hope that this little book will be useful in 
more ways than one. It contains a series of 
samples for experiment, and another for observ- 
ation, each of which by itself should be of 
educational value. 

The experiments are simple, consisting for the 
most part of the application of chemical tests, the 
results of which must be carefully noted, and the 
comparing of weights of certain substances, gen- 
erally called " taking their specific gravity." The 
observations bring in the use of the microscope ; 
these will be better performed by a more elaborate 
than by a cheaper microscope. It is not, how- 
ever, the privilege of everybody to have the use 
of an instrument of very high power. Each must, 
therefore, do his best with the instrument at his 


The time may come when we shall have the use 
of a high class instrument at Technical Institutes 
or even at free libraries, where under proper 
supervision we shall be allowed to examine any 
specimens about which we may require informa- 
tion, and which we may ourselves supply. A 
simple microscope can be bought for a few 
shillings, while an elaborate instrument costs 
several pounds. 

Very much, however, of this book can be done 
without the microscope, although much better 
with it. To carry out the experiments no expen- 
sive apparatus is required. In Appendix No. 2 
will be found the approximate prices of the items 
mentioned in the book. 

The whole forms a course of technical training. 

In the second place, the exercises are confined 
to substances used in food, about which we 
certainly ought to have some information, for on 
the purity of food good health greatly depends. 
Without good food no family can enjoy sound 
health, and no food can be classed as good if it be 

From returns that we have carefully examined, 
we are glad to find that adulteration is decidedly 
on the decrease ; but when cases turn up of such 



extensive character as we frequently see reported 
in our daily papers, we are forcibly reminded that 
we are at any time liable to fall victims to this 

The directions in this book refer to only the 
simplest methods of detecting adulterations. 
Where substances are troublesome of detection, 
or where great accuracy in a common case is 
required, it must be left to a professional analyst. 

Milk is one of the important articles of food 
that suffers most from adulteration, for hardly a 
week passes without some prosecution for adding 
water to it or taking cream from it. Fortunately 
the method of detecting either of these frauds is 
a simple one, not that a buyer can prosecute, but 
in confirming his suspicions by an experiment, he 
can make a complaint to the vendor, and if the evil 
is not remedied he can call the attention of the 
sanitary inspector, who will take up the case. 

Genuine tea and coffee can by very simple 
methods be distinguished from adulterated samples, 
and the same remark applies to many other 
articles of food. 

We are greatly obliged to several scientific 
friends who have been good enough to read 
through the proof-sheets of this work, and one of 


these friends says that "the book is a terrible 
indictment of modern civilization." We hope, 
therefore, that it will be useful in helping to 
improve the aspect of things, by reducing still 
further this evil of adulteration, which we should 
like to see entirely stamped out. 

We must also tender our best thanks to Mr. 
Horace F. Taylor, who made for us the careful 
drawings by which this little work is illustrated. 

John A. Bower. 

June 1895. 













FOODS ... ... ... ... ... 108 




1. Magnifying power of Convex Lens ... 20 

2. Granules of Wheat Starch as seen under 

the Microscope .. . ... ... ... 27 

3. Granules of Rice Starch as seen under 

the Microscope... ... ... ... 29 

4. Starch of Indian Corn as seen under the 

Microscope ... .. ... ... 29 

... 30 

... 30 

... 33 

... 34 

... 35 

... 36 

... 37 

... 38 

... 40 

... 41 

... 42 

... 47 

... 49 


Oat Starch i 

under 1 

bhe IV 



Barley „ 










Tapioca ,, 















Bean ,, 





Potato „ 





Maranta Arrowroot 


East Indian 







The Lactometer 



Test-tube fitted as a 





Tell-tale Milk-jug 




New Milk under the Microscope ... 



Skimmed Milk under the Microscope 



Microscopic appearance of Genuine Cream 



Pure Butter under the Microscope 



Pure Margarine under the Microscope 



Sprig of Tea-leaves 



Single Tea-leaf (under-side), nat. size 




!• Leaves frequently substituted for Tea 



Genuine Coffee under the Microscope 



Genuine Chicory „ „ „ 



Mixture of Coffee and Chicory under the 




Genuine Cocoa under the Microscope 



Crystals of Cane-sugar under the Micro- 




Genuine Honey under the Microscope 



Sample of double-superfine Mustard under 

the Microscope ... 



Pure Mustard under the Microscope 



Crushed Pepper-corn under the Micro- 





This little book is not written with the idea of 
alarming the householder, but rather to put into 
his own hands the methods of detecting ordinary 
adulterations by very simple means — means that 
should always be at hand in the ordinary house- 

We hear it sometimes said, " Oh, I don't believe 
in this adulteration — our food is not adulterated.'' 
Fortunately it is not adulterated to an alarming 
extent; that is, however, not the point; it should 
not be adulterated at all. 

If you buy milk, are you to be supplied with 
milk and water ? You ought to have milk only — 
pure milk ; if you wish to add water you can do 


so without paying fourpence or fivcpence a quart 
for it. If you buy tea, are you to have a mixture 
consisting largely of spent leaves ? Again, if you 
want coffee, are you to have one-quarter or more of 
it made up with chicory ? and butter, is it to be 
simply butter, or is it to be butter mixed with 
other fats, sometimes indeed consisting principally 
of " other fats " ? Margarine and substances used 
in adulterating butter are all very good in their 
places, but not as substitutes for butter; nor has 
chicory the same food value as coffee ; and there 
is no goodness to be extracted from spent tea- 

As we have mentioned, adulteration is not 
now going on to an " alarming " extent, but the 
Summary of Keports of Analysts showed that for 
the year ending 1891, about 12 per cent, of all 
the food sold in this country was adulterated, and 
that the articles that suffered most were spirits, 
coffee, tea, and butter. Since that date, however, 
adulteration has been on the decrease, so that for 
1895 the percentage is not so high as that for 

As coffee comes second on the list, there is 
no doubt but it is adulterated to a large extent ; 
sometimes, we are told, it amounts to 75 per cent. 
In the face of such a statement as this, a little 
guide which helps those who follow it to detect 
adulterations cannot be very much out of 

Since the passing of the Adulteration Act, cases 


of wilful adulteration have been much fewer; but 
even now, hardly a week passes without the ex- 
posure of some tradesmen or manufacturers, who 
have been pounced upon by inspectors, who hand 
the articles over to the public analysts; and when 
the cases are " gone into "in the public court, we 
are astounded at the methods adopted, some of 
them most elaborate, some most flagrant, but all 
showing plainly enough that the public are "being 
taken in." 

Now it is arrowroot, largely adulterated with 
various starches ; then it is milk with 20 per cent, 
or 30 per cent, of water ; then it is the bread ; then 
it is olive oil, that has not a particle of real olive 
oil in it; then it is the mustard, coloured with 
turmeric and bulked with wheaten flour; and so 
we might go the round of substances we buy as 
pure food day by day. 

Now let us refer to the Act, so as to get 
the full meaning of the term "adulteration." 
It says, "The article shall be held to be adul- 
terated — 

" 1. If any substance or substances has or have 
been mixed with it so as to reduce, or lower, or 
injuriously affect its quality, strength, purity, or 
true value. 

" 2. If any inferior or cheaper substance or sub- 
stances has or have been substituted wholly or in 
part for the article. 

" 3. If any valuable constituent of the article has 
been wholly or in part abstracted. 


'* 4. If it be an imitation of, or be sold under the 
name of another article. 

" 5. If it consists wholly or in part of a diseased, 
or decomposed, or putrid, or rotten animal, or 
vegetable substance, whether manufactured or 
not ; or in the case of milk, if it is the product of 
a diseased animal. 

"6. If it be coloured, or coated, or polished, or 
powdered, whereby damage is concealed, or it is 
made to appear better than it really is, or of 
greater value. 

" 7. If it contains any added poisonous ingredient 
which may render such an article injurious to the 
health of the person consuming it." 

The following sections of the Act show its real 
working powers : — 

" Section 6. No person shall sell, to the prejudice 
of the purchaser, any article of food or any drug 
which is not of the nature, substance, and quality 
of the article demanded by such purchaser, under 
a penalty not exceeding £20, provided that an 
offence shall be deemed to be committed under 
the sections following. 

" Section 7. No person shall sell any compound 
article of food which is not composed of ingredients 
in accordance with the demand of the purchaser; 
penalty not exceeding £20. 

" Section 9. No person shall with intent sell to 
a purchaser a substance in its altered state without 
notice, nor abstract from any article of food any 
part of it, so as to affect injuriously its quality, 


substance, or nature, and no person shall sell any 
article so altered without making a disclosure of 
the alteration, under a penalty in each case not 
exceeding £20." 

By the clauses of this Act, it is seen that the 
tradesman is fined on conviction, but in France the 
adulterator is put into prison, and the authorities 
shut up his shop so long as he is in prison ; the 
shop has a label put on to it, stating that it is shut 
up because the proprietor is convicted of adulter- 
ation, and that the proprietor himself is in prison. 
We fancy that such a punishment as this once 
inflicted, prevents most effectually the repetition 
of the folly in the same individual. 

While this Adulteration Act secures to us as 
far as possible that all the necessaries of life shall 
be supplied to us as pure, we on our parts should 
see that we get them in this state of purity. We 
should do nothing to encourage tampering of any 
sort, by offering to take damaged goods at a lower 
price, or by beating down a tradesman from a fair 
price. If goods are offered at an unusually low 
price, something wrong with them may be sus- 

One other source of adulteration ought to be 
noticed, viz. that arising from carelessness. Many 
articles of food are exposed to the air, sunlight, 
and to any amount of dust that may accumulate 
on them, and then these articles are sold as 
pure, and at the same price as fresh goods. 
Take sugar, rice, currants, and raisins, which are 



generally exposed in a tradesman's window ; they 
cannot remain there many days without getting 
covered with dust and dirt, which neither improve 
their appearance nor their nutritive value. This 
ought not to be ; articles of food should always 
be carefully preserved from any source that may 
injure them. 

The most abominable cases of adulteration are, 
however, those where inferior and damaged articles 
are systematically bought, glossed over and made 
up, and sold to the public as pure and of good 
quality, at sometimes a trifle less than is given for 
the best goods. 

In the methods for detection of adulteration 
we shall keep to quite the simplest, such as the 
application of an ordinary chemical test, by 
weighing, and by the use of the microscope. As 
almost everybody learns chemistry now-a-days, the 
application of the simple tests will be interesting 
as well as instructive. At the same time, it will 
require care and discrimination, it will bring out 
the powers of observation, making the experi- 
ment itself a very useful exercise. We are not 
supposing that you are to test every fresh loaf of 
bread that comes into the house, or every pound of 
tea, coffee, or sugar, but that you should select 
samples occasionally, and especially those that give 
rise to suspicion. 

The next process we recommend is one of 
weighing ; for that purpose you should secure a 
thin stoppered bottle, that shall hold exactly 250 


grains of distilled water, or if it is not exactly 
filled by that quantity, the bottle should be 
marked at that point : you can then take the 
specific gravity of milk, butter, oil, and such 
things easily. You must also have a counterpoise 
for the bottle, — this can be managed with small 
shot, — then whatever may be the weight of the 
substance tested, multiply it by 4 ; that will be its 
weight compared with water at 1000. A small 
set of apothecaries' scales and weights will be all 
that is necessary to carry out these experiments 
with fair accuracy. 

Then, lastly, there is the microscope ; in this 
you will take great interest, for it will help you to 
examine many things outside the region of food. 
A low power lens will do for the examination 
of large objects, such as sections of tea-leaves, 
but for the starches you will require a much 
higher power. 

The substances to be examined are to be placed 
on a glass slide supplied with the instrument, to 
be covered with a drop of water, or with a little 
glycerine and water as the case may be, then 
covered with a very thin clear piece of glass, 
supplied also with the instrument. The mirror 
under the stage of the instrument is to be so 
placed that it will throw light on the object to 
be examined. Of course it is quite necessary for 
you to know what you have to look for in each 
case ; we shall therefore give such particulars as we 
go along. In Fig. 1, the diagram shows how the 



double convex lens enlarges the image of an 

We hope that we shall be able to present a 
series of interesting exercises, even if adulterations 
have not to be detected. We propose to give 
directions for preparing such of the tests as we 
apply ; at the same time, we should advise you to 
procure the series neatly done up together in a 
case, so that they are always at hand. 

Fig. 1. — Magnifying power of Convex Lens. 

Where the methods are difficult we shall omit 
them, as they are only suited to the professional 
chemist. You must not therefore look upon this 
as a thorough series of tests for adulterations, but 
only a handy-book giving the simplest possible 
methods of detecting the most glaring and the 
most easily discovered. 

We do not advocate a general raid on our trades- 
men, for most of them are not even to be sus- 


pected of adulterating food ; but if some of them 
will insist on carrying on this fraud, we have no 
business to allow their false and fictitious articles 
to be passed off upon us, because it is condoning 
dishonesty and encouraging trade immorality. 




Bread is often called the " staff of life." Till 
lately, however, it was greatly adulterated, care- 
lessly made, and certainly had no claim to the 
above title. Excellent bread is now made by 
most of our bakers, and since the Bakers' Exhibi- 
tions of the last two years, many improvements in 
mixing and baking have been brought into practice. 
Some of our bakers, however, think they add to 
their repute by attaching to their advertisements 
the results of certain analyses of samples of their 
bread submitted to an analyst. Such a certificate 
is of no value, for the published result only belongs 
to the one specimen referred to. A good and reliable 
baker needs no " puff" of this kind to secure his 
success. Let his bread be always good and pure, 
and his customers will appreciate hirn, and support 
him accordingly. A loaf of good bread can be 
told by the smell, uniformity of its pores, its light- 
ness, thinness of its crust, and that crust baked to 
a nice brown. If when cut, a loaf at a day old 


lias a disagreeable sourness about it, that is not 
a good sample. 

The general adulterations are limited to a little 
alum, a little too much salt, and more potatoes 
than are needed for the leaven. 

Of these adulterations alum is the worst; it 
enables an inferior flour to be made up so as to 
look as white as a better flour ; it also enables the 
flour to take up more water. Too much potato 
imparts a crumbleness to bread, and too much salt 
appeals to the taste. Alum makes bread less 
digestible. This is a great reason why it should 
not be used, especially as food for young people. 
Some bakers will tell you they cannot make bread 
without alum ; that is not true. Persons who 
make their own bread at home do not use alum, 
and with a little practice bread may be very 
successfully made at home ; — we wish it were a 
more universal custom than it is. Once accus- 
tomed to home-made bread, bakers' bread would 
very rarely be used again. 

Now for a ready means of detecting alum. 
Cut a small square out of the crumb of a loaf, put 
it in a plate, pour on it a mixture of a tincture of 
logwood and carbonate of ammonia solution — the 
mixture to consist of equal quantities of each. If 
no alum is present in the bread the pink colour 
will remain, but the presence of alum turns it 
blue. We have never found this test to fail, 
although we have used it for the detection of 
alum for the last twenty years. To ascertain the 


quantity of alum is a more difficult matter, and 
one that requires more chemical skill than we can 
here direct. The detection of potato starch and 
wheat starch after they are made up into bread 
is also one that we cannot detail to advantage. 
They may be examined, however, by the microscope. 
The logwood tincture is easily made, by steeping 
some chips of logwood in methylated spirit, \ oz. 
of the chips to 1 oz. of spirit. Keep it closely 
stoppered. The carbonate of ammonia is to be a 
saturated solution. In using this test take equal 
parts of each, and add three times its volume of 
water before putting it on the bread. This solution 
will detect as small a quantity as four grains to 
four pounds of bread, which is the weight of a 
quartern loaf. 

Sometimes thin strips of gelatine are stained 
with the logwood and ammonia mixtures, and 
applied to the bread to be tested with equally 
satisfactory results. Should any other earthy 
salts be present, like magnesia, the tint will be a 
higher purple still. Alum is the only substance 
you are likely to find. 

The material containing the alum is sold to the 
baker as "hards" and " stuff," and this is really 
a mixture of alum and salt. It is kept in bags, 
weighing from a quarter to 1 cvvt. The very 
worst flours are the most assisted by the use of 
alum, so that even damp and mouldy flour can be 
used, and made up into white bread. 

Good new bread should contain about 45 per 


cent, of water, but we are informed that some 
bakers manage so that the quantity of water 
retained is much larger. They manage this by 
putting the dough into an over-heated oven. The 
outside of the bread is rapidly browned, while the 
inside is not properly cooked. Be therefore 
cautious in buying "slack-baked" or "under- 
baked " bread. 

Well-made and well-baked bread retains this 
normal amount of water for several days, so that 
the dryness noted in a stale loaf is not due to loss 
of water. 

Should carbonate of ammonia be used in bread- 
making — it is for whitening and raising it. If 
the bread is very white it may be suspected. It 
may be detected by mashing a slice of bread 
in cold water that has been boiled for some time, 
or in distilled water. After the soaked bread has 
stood for half-an-hour or so, strain off the water, 
add a few drops of hydrochloric acid, evaporate the 
liquid to dryness, then add some strong caustic 
potash solution. If ammonia is present you will 
at once be made aware of it by its pungent 

To evaporate such liquids as these the tempera- 
ture must not exceed that of boiling water. This 
can be done by using a small saucepan, in which 
a saucer containing the liquid to be evap orated 
takes the place of the lid. The saucepan must be 
kept boiling till the evaporation of the liquid in 
the saucer is complete, and a little space must be 


left between the rim of the saucepan and the edge 
of the saucer for the steam to get away. 

Biscuits and cakes are made with mixed sub- 
stances, so that it is difficult to select which of the 
starches would be an adulteration. When colour- 
ing substances are used, to make up for the 
absence of eggs, that colour is . an adulterant. 
The colour itself may be harmless, but it is never- 
theless an adulterant. If you wish, however, to 
convince yourself that colouring matter has been 
used, dry, and then crush up some of the crumbly 
portion, and make a solution of it, which will be 
coloured according to the quantity that has been 

The larger firms of biscuit manufacturers may 
be relied on as using the best and purest materials 
only, and nothing that is foreign to the substances 
actually required. 

Flour. — When we talk of flour, we mean 
wheaten flour pure and simple, and made of 
grain, free from damage of any kind. Damaged 
wheats are unfit for food, and all the dressing in 
the world cannot make good flour out of them. 

Wheaten flour consists of starch and gluten; 
the latter substance gives to it its nutritive value, 
and is contained in the outer skin of wheat, while 
the starch is a heat-giving substance, and forms 
the inner part of the grain. The gluten gives the 
stiffness to dough, and enables it to rise in bubbles, 
and become light, as it is called. Whole grain is 
used for making brown bread. Coarse brown 


bread is not so easily digested as white bread, or 
as that made from whole grain. 

To examine flour, you must call in the aid of 
the microscope. You must first separate the 
starch from the gluten, by placing a pinch of 
flour on a piece of muslin or calico tied loosely 
over the top of a glass. Let water trickle 
through it, and you can knead the flour at the 

Fig. 2.-Grauules of Wheat Starch. 

same time with the fingers. The starch will pass 
through the cloth, and form a layer at the bottom 
of the glass. Let it settle, then pour off the 
water; put a few grains of this on a glass plate 
for examination. Place a drop of the starch 
solution on a slide, and cover with the very thin 
glass slip. In Fig. 2 we give the shape of wheat 
starch granules ; if you have anything besides these, 


it is due to adulteration. We give illustrations of 
the other starches ; a little practice will soon enable 
you to distinguish one from the other. Micro- 
scopic slides can be bought with the various 
starches ; they cost but little, and to learn from 
these as standards you will soon be able to 
recognize the different kinds as easily as letters 
in the alphabet. A magnifying power of 250 
diameters should be used. As no two starches are 
alike in form, such an acquaintance with them as 
we recommend is a great acquisition. 

Alum, if present in flour, will show itself dis- 
tinctly among the grains of starch ; if its presence 
be suspected, it may also be tested with the 
logwood mixture, by making the flour into a 
creamy paste, and stirring in with it the test 
solution. Should the mixture turn purple alum 
is present ; if the solution keeps its colour, nothing 
of the sort may be suspected. 

Millers tell us that sometimes alum gets in 
from the mill-stone dressings, and in the case of 
the hard Egyptian wheat, alumina does get in 
from clay which fastens itself in minute quantities 
to the outer shell, because the threshing is done 
on clay floors. 

When flour is adulterated with damaged wheat 
it may be detected without the microscope, for if a 
little solution of aniline violet be used with the 
flour, the damaged starch takes up the colour at 
once, while the sound starch refuses to do so. 

If rice starch is used, the microscope will at 


once detect it ; the form of the granule of rice is 

Fig. 3.— Granules of Rice Starch. 

Fig. 4.— Granules of Indian Corn. 

square, as seen in Fig. 3, and very much smaller 
than that of wheat. 

If Indian corn be used in adulteration, it is 



Fig. 5.— Oat Starch. 

Fig. 6.— Barley Starch. 


easily detected by the microscope ; it is more 
irregular in shape, and is much larger. In Fig. 4 
we give the microscopic appearance of Indian 
corn starch. Indian corn is richer in fat, and 
tends to make wheaten flour into a softer dough 
if mixed with it, and gives bread made with this 
mixture a peculiar sweetness. 

In some corn-flours that are sold Indian corn or 
maize is the sole ingredient. 

Oatmeal. — This cannot be made very well into 
bread, but is used largely for porridge and cakes. 
It is as porridge a most nutritious food for 
children ; it, however, requires well boiling. Oats 
are also used for making Emden groats. The 
adulteration to which it is most liable, and to 
which it suffers frequently to the amount of 15 
per cent., is barley-meal. As the starches of the 
two are, however, so different, the microscope will 
soon detect it. Take a little of the mixture, put 
it on the slip of glass, drop on a little water, cover 
the thin glass over it, and put it on the stage of 
the microscope and examine it. Should the two 
starches be present, count the number of granules 
of each, you will then at the same time get the 
proportion of the adulterant and the form of the 
granules. In Figs. 5 and G we give the starch 
granules of oats and barley. A second or even a 
third slide should be prepared and examined in 
like manner. You can then take the average 
result from the three examinations. 




Barley. — This grain is sometimes freed from its 
husk, so as to be used for broths and barley-water. 
In this condition it is called pearl-barley. Mixed 
with flour, as we have mentioned, it makes an 
inferior bread. To detect its presence use the 
microscope ; we referred to the form of its starch 
granule in the last chapter (Fig. 6). The princi- 
pal use of barley is in the manufacture of malt. 
From the malt an extract is made, under the 
name of maltine. This, when prepared at a low 
temperature, has the power of assisting very much 
the digestion of starchy food. 

Under this heading we can deal with the sundry 
" farinaceous foods" made up as fit for infants. 
None of them are so good as meat broths or 
albuminous foods, for the infant digestion is not 
fitted to digest starch foods. 

To detect adulterations, let a portion be dried, 
by the method we recommended, over a saucepan 
of boiling water, and when dried it should be 



examined by the microscope. Compare the gran- 
ules of starch with potato, and those of the other 
figures given. Should potato starch be present in 
larger quantities than other starches, it should not 
be used as infant food, for this form of starch is 
more difficult of digestion than any other. 

Rye. — Rye bread is not a favourite in this 
country, although it is used on the continent. 

Fig. 7.— Rye Starch. 

We give the form of its starch granule in Fig. 7, 

because it is used to adulterate various starch 

foods used in this country. The flour from rye 

contains a gluten, which brings rye-bread nearer 

to a wheaten bread than that produced from other 

grain. Rye makes a very dark bread, and it is 

heavy and poor in flavour. 

Indian corn. — We referred to this substance as 



used occasionally to adulterate wheaten flour, and 
gave the form of its starch granule in Fig. 4. By 
itself it cannot be made into bread, because it 
contains no gluten. It is, however, a favourite 
substance for making cakes in America, and these 
are very nutritious. In this country it is sold as 
corn-flour and as hominy, both of which are 
prepared from maize. 

Fig. 8.— Granules of Tapioca. 

Rice, tapioca, and sago. — These are all forms 
of starch food, and are used largely in this country, 
but in the form of puddings and cakes, mixed with 
other ingredients which assist in their digestion. 
In Fig. 3 we gave the form of the granule of the 
rice grain ; once recognized it is not likely to be 
forgotten. It is small and angular in shape. Mixed 
with wheaten flour, to which, as we have said, it is 



sometimes added for the sake of whiteness, it can 
readily be distinguished. 

By itself rice is the poorest sort of food ; in 
using it for puddings it should be well boiled. 
Ground rice is not easier of digestion than the 
whole grain. If bought in the grain, there is not 
much fear of its being adulterated. 

In Figs. 8 and 9 we give the forms of tapioca 

Fig. 9. — Granules of Sago Starch. 

and sago starch granules, the latter elongated, 
rounded at one end, truncated at the other 
Unlike other starches, tapioca starch is rendered 
gummy by the action of ammonia. 

Maccaroni and vermicelli. — These substances are 
manufactured from hard wheat, and being rich in 
gluten, are very nutritious. To detect adulteration 
with other starches, some of the material must be 


powdered and washed, that the starch portion 
may be examined under the microscope. 

Peas. — Besides using peas as a vegetable iu its 
green state, we use them when fully ripe in their 
dried state. In this condition it is true they 
contain a large amount of nourishment, but require 
considerable cooking to render them digestible. 

Fig. 10.— Pea Starch. 

As green peas they are when cooked easily 
digested and very nutritious. 

In the dried state peas are sold as split peas 
and as pea-flour. Pea-flour is very rarely adulter- 
ated. In Fig. 10 we give the form of its starch 
granule, so that under the microscope it is easy to 
tell whether you have pea-flour or the starch of 
any other grain. 

Beans. — As a food the bean is of about the 



same value as the pea. It is very rarely sold to 
the public as a bean-flour, if so, it is only used to 
adulterate other flours. We therefore give the 
form of its starch granule in Fig. 11. By com- 
paring Figs. 10 and 11 the presence of each can 
be readily detected. 

It is most convenient that these starches all 

Fig. 11.— Bean Starch. 

differ in shape, size, and surface, so that when 
viewed under the microscope they may be so 
readily distinguished from one another. The 
microscope really becomes the most certain guide 
in all inquiries about the kind of starch present in 
any special kind of food. 

Arrowroot. — No starch food is perhaps so im- 
portant to the invalid as arrowroot. This is uot 



on account of the nutriment it contains, but it is 
so easily digested. It is a food which may be said 
to consist of starch only. It is also one of those 
which lends itself to be greatly adulterated. These 
adulterants are starches of other kinds, some of 
which we have been dealing with already. That, 
however, to which we have only briefly referred is 
the very starch that is the most largely used for 

12.— Potato Starch. 

this purpose of adulteration : that is potato starch ; 

its starch granule we give 

in Fig. 12. You see 

how very widely it differs in shape and character 
from the starches we have already sketched. The 
granules vary very much in size and shape — some 
are nearly round, while others are like flattened 
oyster-shells. The larger granules have distinct 
concentric rings surrounding a prominent eye, in 
others this eye is a mere spot at its narrowest end. 


There is, however, no fear of being unable to dis- 
tinguish potato starch. 

That sold as British arrowroot consists very 
largely of potato starch. Now let us see what 
real arrowroot should be. 

We have what is called the East Indian and 
West Indian arrowroots, and also a preparation 
called Brazilian arrowroot, which is really a pre- 
paration of tapioca. Then there is the Florida 
arrowroot. The West Indian is the best, the 
most esteemed being that which is grown in 
Bermuda; next in reputation is that grown in 
Jamaica ; some merchants tell us it is quite equal 
to it. 

Arrowroot is obtained from a species of maranta. 
The roots of the plants are often more than a 
foot long, almost as thick as a finger, and are 
covered with large white papery-looking scales. 
When the plants are about a year old these 
roots are dug up, peeled, and pulped by machinery. 
The pulp is mixed with water, which dissolves 
all but the starch; this settles to the bottom 
of the vessel in which the process is performed. 
It- undergoes several washings, and is finally 
dried in the sun or in drying-houses. Dust 
and insects are shut out by gauze protectors. A 
genuine maranta arrowroot consists of nothing 
but this dry, light, white, opaque starch, a sketch 
of which granules we give in Fig. 13, and of 
an inferior East Indian quality in Fig. 14. 
The latter kind is often used to adulterate the 



former. It comes over to this country in very 
carefully packed cases, and if you get the best 
quality it should feel dry, and produce a slight 
crackling noise when rubbed between the fingers. 
If you buy a cheap quality of arrowroot, you may 
be sure it is inferior, for it is frequently sold in 
this country at a less price than is paid for the 

Fig. 13. — Maranta Arrowroot. 

genuine in the country that produces it. The 
low-priced articles, as we have said, contain very 
little genuine arrowroot, but large quantities of 
potato starch. From this you will see that 
although a starch substance is mixed with starch, 
it makes all the difference in the world as to its 
quality as a food for invalids. Arrowroot starch 
is easily digested, and therefore makes a good 
food for invalids ; while potato starch is not easily 


digested, and should therefore be withheld from 
invalids and children. Sago-flour, rice-flour, and 
even wheaten starch are sometimes used as adul- 
terants. We have, however, so fully described the 
characters of these starches, that when you put a 
sample under the microscope for examination, you 
will very readily be able to see how much of the 

Fig. 14.— E. Indian Arrowroot. 

genuine article you have really got. In studying 
Figs. 13 and 14 you get the distinctive forms of 
the arrowroot. They are convex, more or less 
oval, although somewhat irregular, and they do 
not differ very greatly in size, and are surrounded 
with delicate concentric rings. 

Dry arrowroot is without smell, but when 


dissolved in boiling water it seems to acquire a 
peculiar smell, while it rapidly swells up into a 
perfect jelly. In Fig. 15 we give the form of the 
largest starch granule as it exists in Canna arrow- 
root, or Tous-le-mois. 

There is also a special chemical test which can 
readily be applied to detect these two starches. 

Fig. 15.— Canna Arrowroot. 

Under a drop of sulphuric acid the granules of 
potato starch take up a most beautiful reticulated 
appearance, resembling fir-cones, which gradu- 
ally softens down as the starch becomes gelatinized. 
Upon maranta starch, sulphuric acid produces no 
such change, and it keeps its form for some time 
before it gelatinizes. We have not taken into 
account here that damaged samples of arrowroot 




This will 

are sometimes used in adulteration 
reveal itself, however, under the microscope. 
Should there be mould or animalcule of any kind 
present, you may be sure you have an old and 
damaged sample under examination. This should 
not under any circumstances be used for food. 




Milk. — Good milk should be opaque, white, but 
have no solids floating in it, and be of a sweet, 
agreeable taste. 

Perhaps no food substance sold in large quan- 
tities is so much adulterated as milk. The great 
adulterant is water. It also suffers by having a 
portion of its cream taken away before it reaches 
the purchaser. Chalk and other substances said 
to be used in adulteration are so rarely met with 
that we need not trouble ourselves about them. 
We have never discovered chalk among the 
samples we have examined. The adulteration 
with water, however, is a very serious matter, 
although it seems so simple. 

In London alone, very nearly £1,500,000 is 
spent yearly for milk ; and according to statements 
which are official, the average adulteration with 
water extends to one-twentieth of the whole, 



which means that the cost of the water sold as 
milk in London alone, amounts to between £70,000 
and £80,000. 

Milk is especially the food of the young, and 
contains everything they want in the way of food 
— it is a type of a perfect food ; but added water 
robs milk of its value in this respect, according to 
the amount added. 

Cow's milk contains solids amounting to one- 
seventh of its whole weight, of which one-third is 
sugar, a little less than one-third is cheese, and 
one-quarter milk fat. The total solids in pure 
milk vary from 10 '33 to 15*83 per cent. This 
arises from circumstances we cannot discuss here ; 
we mention it to show how difficult it is to state 
accurately the extent to which some samples have 
been watered. 

Another mischief which is too often overlooked 
is, that the water used for adulteration is frequently 
foul, and may contain germs of disease. The out- 
break of several epidemics in various localities 
has indeed been traced to this source. This 
danger is referred to by a writer in these terms : 
" Worse than the process of watering down, which 
does not merely impoverish good milk, it may 
happen that the water itself is impure, and a 
bucketful of foul well-water from a distant farm 
may mean a hundred deaths in one London 
parish." To avoid mischief from this last form of 
adulteration, milk should always be boiled before 
being used. 


As a food, cooked milk possesses only the same 
value as uncooked. 

To be perfectly sure of the extent to which milk 
is adulterated, chemical analysis is necessary, but 
the following tests are sufficiently trustworthy for 
a general estimation. 

First, by taking its weight compared with water, 
i. e. its specific gravity. 

Supposing a quantity of water is taken which 
weighs 1000 grains, that same quantity of milk 
should weigh from 1029 to 1032 grains. This test 
can be carried out with the bottle we have already 
mentioned, which contains 250 grains of distilled 
water, for whatever the same bottle will weigh when 
filled with milk, will be due to the milk. Sup- 
posing we find that the bottle when filled with milk 
w T eighs 7 grains more than when filled with distilled 
water, that will be 257 grains ; multiply this by 4, 
and we have 1028, i. e. a specific gravity of 1-028. 

Another method of taking the specific gravity 
of a liquid, is to note how far a floating body sinks 
in it. This is the principle on which the lacto- 
meter (Fig. 16) is made. It sinks to a certain 
depth in average milk ; if the milk is watered 
simply, it sinks to a greater depth; and if anything 
is added to increase the specific gravity, it does 
not sink to so great a depth. The instrument can 
be bought for about a shilling, and it is marked to 
sink to a certain point in good average milk : 
should the milk be of extra good quality, it does 
not sink so far; if of a poorer quality through 


added water, it sinks to a lower level, and this 
depth corresponds to the quantity of water 
added to the milk, provided it has not been 
robbed of its cream. The scale marked on 
the stem of the instrument enables you to 

Fig. 16.— The Lactometer. 

compare the quality of the milk with the depth 
to which the instrument sinks. It happens, how- 
ever, sometimes, that milk from which cream has 
been removed is adulterated with milk of a 
similar quality — that is, skim-milk is added instead 


of water ; that increases the specific gravity, 
although the milk is poorer, for the skim-milk 
supplies it with solids, not fat, above its natural 
quantity. Owing to this, the lactometer cannot 
be looked upon as so reliable an instrument as the 
creamometer, which we will now describe. 

The creamometer takes into account the amount 
of cream which rises to the surface when the milk 
is allowed to stand quietly for some time. When 
both the creamometer and lactometer are used 
with the same sample of milk, we get more reliable 
results than when we take each separately. 

A creamometer may be made from an ordinary 
test-tube, not less than half-an-inch in diameter, 
better still three-quarters of an inch, and about 
five inches long. Take a slip of paper — a slip 
from the edge of a sheet of stamps is best, because 
it is already gummed ; cut it off five inches long. 
With a pencil, mark this off in. five equal divisions, 
and mark an inch at one end into ten equal 
divisions. Number the larger divisions, then 
paste the strip along the outside of the tube, in 
direction of its length, with the divided inch- 
measure at the top. Allowance must also be 
made for the rounded bottom of the tube. Fix 
this tube upright into a large cork or bung, and 
you have such an appliance as shown in Fig. 17. 

To use it, pour into the tube sufficient milk 
to fill it to the height of the top edge of the paper 
slip ; stand it aside in a cool place for six hours. 
At the end of that time read off the divisions 


occupied by the cream that has risen to the 
surface. Double that number, and you have the 
proportion in 100 parts, or the percentage of 
cream. If your sample of milk is good and pure, 
you will have from twelve to fourteen parts 
occupied by the cream ; if a poor watered specimen, 
it may be only half that number ; should it fall 
below ten per cent., you may be tolerably certain 

Fig. 17.— Test-tube fitted as a Creamometer. 

that water has been added, or that cream has been 
taken away. The quality of the milk may be fairly 
estimated according to the number of divisions 
occupied by the cream. A watered or a robbed 
sample throws up much less cream in a given time 
than a pure sample. 

Tubes on feet, with divisions marked on them, 
are made for this purpose. One may be bought 
for a small sum ; while within a few months 
a " tell-tale " milk-jug on this principle has 
been patented and put into the market. On 


this jug, markings are given for the pint, half- 
pint, and quarter-pint; on handing this jug to 
the milkman for your supply, if he gives short 
measure it is at once detected. The estimate of 
cream is taken in the same manner as in the tube 
method, three scales being marked on it, for 
average, good, and very good milk. A sketch of 
this jug, which is sure to be a favourite with all 
but the milkman, we give in Fig. 18. 

Fig. 18— Tell-tale Milk-jug-. 

This method of testing the quality of milk is 
much more reliable than with the lactometer 
alone, owing, as we have said, to a form of adulter- 
ating new milk with skimmed or separated milk. 
As the skimmed milk has been merely deprived 
of its fat, it will still contain the other solids which 
are not fat. A milk so doctored will show a high 
specific gravity, although the yield of cream will 
be small. Curiously enough, it was by such an 
instance as this that the fraud of adding skim- 
milk was discovered. 

It is only by a thorough analysis that the purity 
of milk can be fully certified, but this ready 


method of cream raising gives a general and 
fairly accurate estimate as to whether it has been 
adulterated or not. 

The microscopic examination of milk is inter- 
esting. The quantity of fat particles in a good 
rich milk, contrast most favourably with the 
sparsely present particles in a watered or skimmed 
sample. In Fig. 19 we give a microscopic ap- 

Fig. 19.— New Milk. 

pearance of a sample of new milk ; and in Fig. 
20 a sketch of skimmed milk. The temptation 
to water a sample is so great, and so easily done, 
that the seller often does it without thinking of 
the consequences. 

When milk is taken, it should not be stood near 
to any strongly-scented substances, for it so readily 
absorbs the sweet as well as the evil scents. In 


applying any of the above tests, the milk should 
always be thoroughly mixed, so that your sample 
for experiment is neither from the top nor from 
the bottom of your jug. 

When it is impossible to get fresh milk, con- 
densed milk may be used. Several good brands 
of this article are in the market. These tinned 
samples consist of milk reduced by evaporation to 

Fig. 20.— Skimmed Milk. 

about one-seventh of its original bulk, and to this 
a little sugar is added to keep it good. 

The greatest care should be used in selecting 
water to add to it; it should be of the purest 
quality, quite above any suspicion of contamin- 
ation. Some persons prefer the sterilized milk 
on this account, for in it there is no chance of any 
germ of disease, such as may arise from impure 


water. When condensed milk is mixed, it is well 
to test it occasionally for the amount of cream it 
will throw up. 

Cream. — Experienced dairymen tell us that 
cream may be thin and yet rich in fat, so it may 
be thick, and yet not contain more than an average 
amount of it. The cream that rises first to the 
surface of milk is generally thin in quality, yet 
it contains really more fat. 

When you take the cream off the milk that you 
have yourself set for raising, you are tolerably 
sure of its purity; it is in the bought samples 
that adulteration comes in. The colour should be 
noted ; it should not be white, but a rich yellowish 
tinge, that has a speciality about it that we call 
" creamy." 

Starch is sometimes said to be used for stiffen- 
ing cream. It may be detected by making a 
little solution in warm water, and if on adding a 
few drops of iodine tincture the colour should 
turn blue, starch is present ; if there is no change 
in colour, starch is of course absent. 

Boracic acid is sometimes added to cream to 
keep it from going sour. Most persons do not 
look on this as adulteration. In putting aside the 
milk for cream we should remember — 

1. Milk at a falling temperature from 45° F. 
to 40° F. raises the cream most rapidly. 

2. At that temperature the volume of cream is 

3. The yield of butter is more considerable. 


4. The skim-milk, butter, and cheese are of a 
better quality. 

In Fig. 21 we give the microscopic appearance 
of the fatty particles in genuine cream. Artificial 
cream is said to be made with albumen and cream 
faintly coloured with annatto. 

Butter. — This is derived from the solid fat of 
milk, and besides this it should contain nothing 

Fig. 21.— Genuine Cream. 

else, unless the butter is required to keep, then a 
little salt should be added. 

To secure good butter the fat should be well 
washed with cold water, so that every trace of 
buttermilk is taken away, or the butter is likely 
to go bad. 

Butter is often adulterated with other fats, 
especially with a substance called margarine. 
Margarine is not bad in itself, but should not be 


passed off as butter. Butter is most easily 
digested of all the fats ; margariue is not so 
easily digested. To detect margarine in a sample 
of butter is not very easy; if you can arrange 
your experiments so as to fix on the temperature 
at which the fat melts, this is a great help towards 
its detection. 

Margarine melts at 88° F., but genuine butter 
does not melt till 95° F.; other fats, like lard, do 
not melt till a higher temperature still is reached. 
In melting a sample in a test-tube by means of a 
hot-water bath, should it remain solid at a higher 
point than 95° F., some other fat than margarine 
is used as an adulterant. 

To ascertain the melting point, this plan may 
. be adopted : place a sample of butter in a small 
test-tube, let it be held in a vessel of water, 
placed over a lighted lamp ; in this vessel suspend 
a thermometer. A small beaker of water standing 
in a tin saucer containing a layer of sand is a 
good contrivance for the outer vessel, you can 
then see through the water immediately the fat in 
the test-tube begins to melt. As the temperature 
rises, carefully watch the thermometer, especially 
after the temperature 85° F. is reached ; should 
the temperature go on rising to 95° F. before you 
can see through the liquid yellow fat in the tube, 
you have no margarine present ; should it run to 
fat before reaching this temperature, margarine is 
present. If your specimen is pure butter, lift it 
out of the bath when at 95° F., and on holding it 


up to the light you have a nearly transparent 
liquid of a bright yellow colour. 

You may say that this is a troublesome process ; 
so it is, for it requires great care to detect the 
exact temperature at which the fat melts ; it is, 
however, a most satisfactory test. To detect this 
melting point some analysts use a little weighted 
glass float, which sinks into the fat when it 
becomes liquid. The temperature is noted imme- 
diately the weight sinks. 

The method may be rendered a trifle easier 
perhaps by reducing the size of the test-tube, so 
that the column of melted fat to look through is 
exceedingly small. The melting point is the best 
indicator of pure butter, so that if rather trouble- 
some, it is satisfactory as to the result. 

We give the melting points of a few of the fats 
used in adulterating butter; compare these, and 
you have an indication of the fat you are 


Melting points of — 


31-3° C. 

88-3° F. 




Butter (true) 



Beef dripping 



Veal „ 



Mixed „ 









The microscope will be a help in the case of 
butter. Melt a little butter, drop it on to cold 


water : you will get a thin layer of butter fat, 
which can be examined with the microscope. If 
it is pure you will get a uniform pattern ; if 
margarine be present, you will have a number of 
small patterns. In Fig. 22 we give the micro- 
scopic appearance of pure butter. Of course if 
starch is used in such adulteration the microscope 
will reveal it at once. 

Fig. 22.— Pure Butter. 

There is one other plan, which is perhaps 
simpler, i. e. take a small piece of butter, draw 
through it a piece of darning-cotton, so that 
you have a miniature candle. Set light to the 
cotton, let it burn for a very short time, then blow 
it out. If there is no disagreeable smell left 
behind, your sample is probably good pure butter; 
if, however, there is a smell of tallow, or any such 
disagreeable odour, you may be sure your Bample 
is not a pure butter, 


Batters that are brought to this country must 
not be condemned because of having lost their 
colour, for sometimes the butter in the centre of 
a tub will be quite white, and yet be a pure 

Frozen butters are brought over here from 
Australia now, and work up exceedingly well. Of 
imported butters, the Danish is generally the best 
to buy. 

If butters have too much salt this must be 
considered adulteration. Fresh butters should 
only contain a little more than 1 per cent., and 
salt butter about 5 per cent. ; any excess beyond 
this is not needed. Salt can be detected readily 
with the microscope. 

Margarine. — Pure margarine is a very whole- 
some fat, and for cooking purposes, such as making 
pastry, it is to be preferred to much of that which 
goes by the name of " cooking butter." It is 
made from refined "butchers' fat," worked up 
with oil and milk. To make it saleable it is 
necessary to colour it so as to look like butter. 

In its turn it comes in for a share of adultera- 
tion with other inferior fats. In Fig. 23 we give 
the microscopic appearance of pure margarine. 
As we have mentioned, margarine is not so 
digestible as good butter fat, but it is better to 
eat with bread than a badly made butter. It is 
perfectly wholesome, and its flavour is often very 
good, but it is less delicate in its flavour than 
butter, Butter to the palate is the most delicate 



as well as the most digestible fat among our food 

Cheese. — Cheese is made from the solids in 
milk, including sometimes all its fat, and some- 
times merely a part, often a very small part, of the 
fat. Some of the richer cheeses are made of 
cream added to new milk ; the curds mix with the 
globules of fat, all being put into the press 

Fig. 23. — Pure Margarine. 

together ; the mass moulds into a solid lump, from 
which all the liquid soon drains away. 

There is not much adulteration in cheese, 
though each make has its own characteristics. 
Some of the poorer cheeses are made from skim- 
milk only ; the better class vary according to the 
quantity of fat put into them, c. g. a stilton or 
cheddar is very much richer than a Wiltshire or 
Suffolk cheese. We mention this, because taking 
fat from milk used in cheese-making does not 
come under the term adulteration, but constitutes 


the character of the cheese. Various ferments are 
added to ripen cheeses, and to give them special 

If very thin slices of cheese are examined by- 
means of the microscope, you will in most cases 
be able to detect it, if any foreign substance is 

The yearly exhibition of the Dairy Farmers' 
Association, which takes place at the Agricultural 
Hall, forms a splendid object-lesson in all that 
appertains to the articles of food we have dis- 
cussed in this chapter. Everything connected 
with the dairy is shown with all the latest 
improvements for separating the cream from the 
milk, the making of butter and cheese. There 
is also a show of cows — especially those which 
are the best milk-producers. It also points out 
the fact, that while so many wheat-growing 
farmers have been ruined, dairy-farmers have not 
only floated, but been able to make profits. It 
also suggests the question, Why should not we in 
England have more land devoted to dairy-farming, 
seeing that the yearly imports of butter, cheese, 
condensed milk, and eggs amount to several 
million pounds sterling ? A large portion of this 
produce comes, it is true, from our own colonies; 
but for butter, Denmark alone sends us £5,280,000 
worth. This is rather more than half the total 
quantity imported. 

The children of this country would certainly be 
benefited by a better milk supply, for it furnishes 


them with every food requisite for making 
material for their healthy growth. Some children — 
London children in particular — do not have nearly 
as much milk as they should. According to various 
returns for the United Kingdom, the total yearly 
consumption represents about sixteen gallons of 
milk per head : this is only about one-third of a 
pint per day. Suppose we take London alone, 
where it seems that children want it most, the 
average falls to six gallons per head for the year. 
Among the poorer classes it would be a great 
improvement if parents spent more on milk and 
less on alcoholic beverages. The whole family 
would be better for the change, especially the 
children. We hope that the results of Technical 
Education in the production of dairy produce will 
have the effect of increasing the quantity and 
improving the quality, and cut out altogether 
every species of adulteration in this class of food. 




Tea. — Although we have two kinds of tea re- 
cognized in the market, viz. black and green, we 
must bear in mind that they both come from the 
same plant. We ought also to know that the 
active substance for which tea is drunk only 
exists in this plant, which is said to belong to 
China, and in one other, that is a native of 
Paraguay, which is called Paraguay tea. 

This active substance is theine, and belongs to 
the same class of alkaloids as quinine. In its 
pure state it is a white, needle-like crystal. You 
will be inclined to ask, how it is we have black 
and green tea if they both come off the same 
plant ? The difference is entirely due to the time 
of gathering the leaf and the manner of its 
preparation. To learn what kind of a leaf it is 
look at Fig. 24, where you have several represented 
on the stalk, and in Fig. 25 a plain ordinary leaf 
spread out flat. The flowers of the tea-plant are 
white, something like our wild dog-rose, but smaller, 



being only about an inch across. The leaf is 
rather fleshy, and seldom exceeds two inches in 
length by one inch broad ; its edge is serrated 
very regularly nearly to the stalk, the veins run 
almost parallel to each other from the midrib; 

Fig. 24.— Sprig of Tea-leaves. 

Fig. 25.— Single Tea-loaf 
(under-side); nat. size. 

before the border of the leaf is readied these ribs 
turn inwards, leaving the border clear. To see 
whether you have tea-leaves or not, pour a little 
warm water on to a small quantity of tea, so as to 
soften the leaf, then take pains to spread it out 
with the back of the leaf upwards, look at it with 



the magnifying glass, and compare it with Fig. 25. 
The leaves are of different sizes, and some are 
much broken, but you will readily see the shape 
of the leaf and the arrangement of the veins. 
Various leaves have been substituted for tea- 
leaves, although this is not done to any great 
extent. In Figs. 26 and 27 we give the forms of 
some of the leaves that are occasionally substituted 
for tea. 

Fig. 26.— Rose-leaf. Fig. 27.— Beech-leaf. 

(Frequently substituted for Tea.) 

The chief adulterant is due to spent leaves — 
i.e. leaves which have already been used for 
"making tea;" these are collected, dried, and 
bought up again. 

The most recent "enormous" case is that 
reported in the London daily papers of Monday, 
October 22, 1894, which report detailed how the 
discovery was made, the plan adopted to get such 



rubbish into the market, and the cheap rate at 
which such tea can be sold, and the amount of 
fine really inflicted with the amount of fine that 
law allows to be inflicted. These spent leaves 
may be mixed with inferior or with good teas, 
and the quality of the mixture will regulate the 
price at which it comes into the market as " cheap 

Sometimes leaves are coloured; this colour is 
generally mixed with a little weak gum-water. 
If leaves look very green or very black colouring 
matter may be suspected. Take a little of the 
tea — a pinch — rub it between your fingers, which 
must be dry, drop the powder into a wine-glass 
of clean cold water, stir it about, and if the water 
is coloured, the colour comes from the surface of 
the tea. If there is much colour, add to the 
water a little potassium ferro-cyanide, the solution 
will then turn to a bright blue, like Prussian blue. 
This shows that an iron salt has been used for 
coating the outside of the leaf. If a black 
powder comes off into the water, that is black- 
lead, which is often used for spent leaves. Some- 
times rubbing dry tea between folds of white 
calico takes off the colour if the tea is faced with 
these powders. 

To detect the spent leaves, take a very small 
quantity of tea, pour boiling water on to it, let 
it stand for a short time, then pour it off, and add 
a second supply of boiling water ; see how often 
the operation can be repeated so as to give a 


coloured solution. If the leaves are spent leaves, 
your second decoction will be very light in colour. 
In a good and genuine sample of tea this operation 
may be repeated several times. 

There are various methods of detecting adulter- 
ations. We do not know of a simpler or better 
than that adopted by tea-tasters in the tea- 
merchants' offices. They take as much tea as will 
balance a sixpence, put it in a cup, cover it with 
boiling water, let it stand for five or six minutes ; 
the colouring matter will go either to the bottom 
or come to the top. The strength and aroma of 
the infusion is a true representative of the quality 
of the tea. 

Some recommend that an easy way to be sure 
of the quality of tea is to take the specific gravity 
of the infusion. The solution is made by taking 
one part of dry tea and ten parts of water, quickly 
raised to the boiling point and then filtered; 
genuine teas will give a solution of between 1010 
and 1014, taking water at 1000. This test can 
be applied with the bottle we recommended in 
Chapter I. We give the average results of some 
experiments in this method of testing teas. 

From ordinary Congou, Sp. gr. = 1009*88 

Hyson „ „ 1013-67 

Gunpowder „ „ 1012-77 

With Indian teas : — 

Congou „ „ 1012-68 

Pekoe „ „ 1014-32 

Hyson „ „ 1013-80 

We add another hint on removing the facing of 


teas. Take a small sample, cover it with cold 
water, shake it, and pour the liquid oil' quickly. 
Notice if any sand goes to the bottom. The 
quantity of theine is about 3 per cent, in good 
teas. From a series of experiments we note that 
100 grains of the following teas yielded — Congou 
2f grains, fine Congou 3 T V grains, gunpowder 
2f grains, Assam 3 J grains of theine respectively. 

The most satisfactory plan is to take the weight 
of the ash of the dry tea, which rarely exceeds 
5*5 to 6 per cent, if the sample is genuine, but 
this process is too troublesome to give at length 

Another plan is to examine sections of tea-leaves 
by means of the microscope, but we think the 
methods we have already given will suffice for 
our purpose. 

We may be allowed to add a caution about 
making tea. Do not use water that has been 
boiling for some time, but use water just on 
the boil. Do not let it draw too long; five or 
six minutes is ample time, if you wish to secure 
the delicate aroma of the tea. 

Very pure tea is now made up into tabloids; 
these are exceedingly convenient if a cup of this 
beverage is needed in a hurry. 

Do not buy the cheapest teas, nor dusty teas. 

Coffee. — In taking coffee we use the berry and 
not the leaf. The aromatic qualities of the coffee- 
berry are developed in the roasting, as those of 
the tea-leaf are in the drying. We advise all 


householders who use coffee to buy it in the fresh- 
roasted berry and not in the ground condition; 
not that the berries are entirely free from adulter- 
ation, but they are less liable to it. Coffee 
contains caffeine, that is, a white, needle-formed 
crystal, like theine; in fact, caffeine and theine 
are the same substances. Chemists tell us that 
the substances used in adulterating coffee are 
numerous, and include lupine seed, beet-root, 
parsnips, beans, dandelion-root, burnt malt, date 
stones, and acorns, but that chicory is the most 
extensively used, and, as far as our experience 
goes, it is the only one we need to look for. If you 
have the roasted coffee-berry, take a sample out 
of a well-mixed packet, spread them out, see that 
they all have the character of the berry ; if they 
are broken, or are soft, examine them. You can 
recognize coffee-berries by biting or crushing them. 
Chicory, beans, and parsnips roasted and cut up 
about the size of the coffee-berry, cannot be passed 
off as such if care is taken in the examination ; 
besides, they are always somewhat moist and 
sticky. At a mere glance they may be passed off 
as coffee. 

When bought as powder, then advantage is 
taken of the fact that ground chicory and coffee 
look very much alike — or chicory finely powdered 
coats the ground coffee. Chicory can easily be 
detected by the -smell. There is a sickly sweet 
smell in the mixture, but a clean aromatic 
smell with pure coffee. Take a pinch of the 



mixture, drop it into a glass of cold water ; if the 
powder floats, and the water is but slightly col- 
oured, no chicory is present ; if some of the powder 
falls directly to the bottom of the glass, giving the 
water a reddish muddy appearance, you may be 
sure that chicory is present : the coffee floats, the 
chicory sinks. Coffee gives very little colour to 
cold water during: the first fifteen minutes. To 

Fig. 28. — Genuine Coffee. 

know the extent to which chicory is present, it is 
best to take a sample and look at it under the 
microscope. In Fig. 28 we give a microscopic 
sketch of genuine coffee, and in Fig. 20 of genuine 
chicory, and in Fig. 30 coffee and chicory mixed. 

To get a standard for examining these, take a 
coffee-berry, break it up in a mortar — not in a 
mill, unless it has been kept for coffee grinding 


only — drop the powder into water; see how it 
acts, for all coffee should act alike. The powder 
is slightly greasy — that prevents it from being 
immediately wetted. Take a little pure chicory, 
drop some into water in the same way ; notice how 
quickly the water becomes coloured. Chicory 
contains a good deal of sugar — coffee contains very 

Fig. 29. — Genuine Chicory. 

little. It must, however, be remembered that 
chicory contains no theine whatever, and there- 
fore is of no value compared with coffee. Some 
people like the flavour of coffee better when a 
little chicory is present. The better way is there- 
fore to buy whole coffee by itself and chicory by 
itself, and mix them just before using. 

Examine a little pure coffee powder, and also a 


little chicory powder, separately, under the micro- 
scope, and get familiar with their appearances, so 
that you can readily recognize them. None of 
the other substances we have named as used 
for adulterating coffee contain theine. Chicory 
is sometimes adulterated with other things, but 
as it is so cheap, we do not think this is largely 

Fig. 30. -Coffee and Chicory. 

done. The best coffee costs from Is. Sd. to 2ft, p r 
lb., the best Yorkshire chicory, 4^. per lb. 

It is quite legal for a tradesman to sell chicory 
mixed with coffee if he labels the packet as a 
mixture of the two, and the proportion of the 
mixture. The extent to which chicory is used 
varies from 40 to 80 per cent., and some samples 
have been found to contain as much as 90 per 


cent. Some persons are so fond of chicory, that 
we have heard the story more than once of a 
mother who sent her son for " an ounce of coffee 
all chicory." 

The merchant's test is much the same for coffee 
as for tea, only the quantity of coffee used for a cup 
of solution is as much as balance a shilling. Treat 
it in the same way as for tea, and if it comes out 
right you need try nothing further. It is easy 
and truthful. 

We ought perhaps to mention the specific 
gravity method, as we did so for tea. Taking the 
same standard, pure coffee infusion has a specific 
gravity of 1009^-, and chicory a specific gravity 
of 1021f, while a mixture of 60 of coffee and 40 
of chicory will give a solution having a specific 
gravity of 1014J. 

Do not buy canister coffees if you wish for real 
good coffee ; see that the berries you buy are 
not broken ; see that they have been recently 
roasted, or warm them upon a metal plate just 
before grinding. Beware of coffee essences. 




Cocoa. — The active principle in cocoa, corre- 
sponding with theine in tea and coffee, is theo- 
bromine. It differs from theine in appearance, 
not being crystalline. 

The nut is so rich in fat — more than half the 
nut is fat, which goes under the name of cocoa- 
butter ; to tone down this, starch and sugar were 
formerly largely used, making soluble and other 
forms of cocoa. Since, however, the process has 
been adopted of making cocoa-extracts, by press- 
ing out a large proportion of the fat, this need 
has not existed. In the soluble extracts of Fry's, 
Cadbury's, Van Houten's, Schweitzer's, and other 
makers, the fat has been reduced in quantity, and 
the cocoa has by special treatment become more 

"Cocoa nibs" is the simplest and most genuine 
preparation of this nut, and should simply consist 
of the roasted seeds, crushed — not to powder — 
then sifted away from the husk; all the husk 


should be removed. Chicory may be used in 
adulteration of cocoa nibs, and may be detected 
as directed for coffee adulteration. 

In cocoa pastes, starch, flour, and colouring 
matter have been found. Red lead has been 
employed for this purpose. If this is suspected, 
dissolve a little of the paste in water, and add a 

Fig. 31.— Genuine Cocoa. 

little strong acid — nitric acid, for instance — then 
add a little solution of iodide of potassium. A 
beautiful yellow colouration will be at once pro- 
duced. The usual test for starch may also be 
applied. To get an idea of the quantity of starch 
in any paste of this kind, the microscope must be 
employed. In Fig. 31 we give a sketch of genuine 
cocoa under the microscope. 


The dry powder extracts of cocoa may be 
examined by the microscope as the best guide to 
the presence of any foreign substance. If chicory 
is suspected here it can be detected in the usual 
way. A method is adopted now by which a large 
portion of the fat may be extracted from the nut. 
This, as we have already mentioned, does away 
with the necessity of adding starches, arrowroot, 
sugar, and other substances to make the cocoa 
soluble and digestible. With all the natural fat 
present in the nut, it is much too rich for a 

The cocoa-butter which is extracted is used for 
making the inside of the chocolate-creams and 
other sweets. It has the special quality of always 
retaining the flavour of the cocoa-nut, and never 
going rancid or bad. This cocoa butter at 24° C. 
(75° F.) has a creamy colour, and all the delicious 
flavour of the cocoa-nib. It is quite soluble in 

To detect adulteration in cocoa: the chicory 
can be discovered as shown in the last chapter, as 
when associated with coffee, while the foreign 
starches can be recognized by the microscope, or 
by their forming a jelly when mixed with boiling 
water. Starch can also be detected by the iodine 
test. The husk will be recognized by its rough- 
ness, or at once by the microscope. If the powder 
looks very red it may point to an adulteration 
from iron oxide (iron rust). Burn a little — if iron 
is present it will be left behind ; add a few drops 


of sulphuric acid to the ash, then potassic ferro- 
cyanide, and Prussian blue will result. We do 
not think, however, that our readers will find this 
substance present. 

The best security is to buy the best prepara- 
tions by firms who always send the best goods 
into the market. Among common and careless 
preparations of cocoa, there are still some very 
curious mixtures in the market, and it is to these 
that our remarks on adulteration are chiefly- 

The shape of the cocoa starch granule as shown 
in the figure is so distinctly different to any of 
those we have already given; moreover, it is 
coloured, so that you cannot mistake it for sago, 
arrowroot, wheat, or potato starch, which are the 
substances most generally used in adulteration. 
Sugar may also be detected by its crystalline 

Chocolate. — In the various forms of chocolate 
which have to be made up into soluble cakes, 
with some flavouring matter, starch to a small 
extent and sugar must not be looked upon as 
adulterants. To detect the chicory in chocolate 
or any preparation of cocoa cold water must be 
used, for warm water would bring the cocoa into 

In the mixtures of cocoa and milk the same 
remarks apply ; the cocoa, however, must be 
separated, and perhaps this would be too trouble- 
some a process to be easily carried out. 


When preparations of cocoa or chocolate are put 
up by good makers, who can be relied en, none of 
the foreign substances we have mentioned find 
their way into the mixtures. It is only with 
inferior, cheap mixtures that the presence of these 
need be suspected. At the same time, it is well 
to have at hand the means to adopt, for even if 
no adulteration is to be suspected, a trial exercise 
is an instructive exercise. 

Essences and pastes of cocoa and chocolate 
mixtures with milk are sometimes not to be 
relied on. Suspected samples should be examined 
by the microscope. Take a portion of the paste 
from about the centre of the tin, make it into 
solution, and examine a drop of it. Repeat this 
with two or three drops. You should be able to 
see the fat of milk, cocoa, cocoa-starch, and sugar. 
By examining several drops you will see whether 
the mixture is uniform in quality, as well as 
convince yourself whether anything is present that 
ought not to be present. 

Cocoa is a very nutritious beverage, which really 
partakes more of the nature of food than a drink. 
It is especially good for the young and the aged. 

A peptinized cocoa is prepared specially for 
invalids; but, as we say, it is in the "prepared 
cocoas," as they are called, that we become sus- 
picious of adulterations, where the introduction of 
foreign substances might not legally be (tolled 
adulterations, yet the value of the cocoa would be 
perhaps impaired by the introduced substance. 


The best form in which to buy cocoa is the 
concentrated cocoas of the good makers, and the 
cake chocolates by the same makers. They are 
clean, wholesome, and nutritious. 

Chicory. — We have mentioned chicory as the 
substance used in adulterating coffee and cocoa, 
but we have not noticed how it is itself adulter- 

This substance grows in the form of a root very 
much like a parsnip, being itself the root of the 
wild endive. The roots are sliced and dried, then 
roasted, but on roasting they develop no such 
active principle as distinguish tea and coffee, 
therefore they have no refreshing principle. It is 
on account of its cheapness that it is mixed with 
coffee. Cheap as it is, however, it has been 
adulterated with dog biscuit, mustard seeds, 
roasted grain, burnt bread. These were used as a 
coffee substitute. Chicory seems to be a substance 
to which some manufacturers think they may add 
without stint " odds and ends " that cannot other- 
wise be profitably employed. That manufactured 
by the best makers is, however, uniformly good, 
and in fact may be said not to vary at all. 

In detecting adulteration in some such samples 
as we have pointed out, the only method is to 
keep a good memory of what pure chicory is like 
under the microscope, and compare other samples 
with it. 

Date coffee. — Some time ago a coffee called 
date coffee was introduced into the market, to 



supersede in some measure the old-fashioned 
beverage. It did not hold its place long. We 
should not have mentioned it here, but it is 
sometimes now used to adulterate ground coffee. 
The substance was made up with about one-fourth 
part of coffee-berry and three-fourths of roasted 
dates. Such coffee has too much the flavour of 
"all chicory," that those who are judges of coffee 
cannot be very well deceived by its flavour. Its 
presence in coffee may be detected by the methods 
mentioned for the detection of chicory. It acts 
very much like burnt sugar. 




We derive our sugar from two sources, viz. the 
sugar-cane and beet-root. The former generally 
goes under the names of Demerara, Barbadoes, 
Jamaica, Porto Rico sugar, and is to be preferred, 
for with all the care that is spent in its manu- 
facture, we never seem to get rid of all impurities 
in the beet-root sugar : a disagreeable smell hangs 
about it, especially if it is kept a long time. It 
is equally sweet, but we do not think it is equally 

Sugar is generally sold in a state of great purity, 
in fact some chemists make the general assertion 
" that sugar and bread are the only articles of food 
sold pure." 

Pure sugar should have a nice clean crystal, 
clean sweet taste, and should completely dissolve 
in cold water. There should be no dampness, or 
rank smell, or a dingy-looking soiledness about it. 
Try samples of loaf and moist ; look at them with a 


magnifying glass ; dissolve portions in cold water — 
no sediment should be left. Burn a specimen — 
very little ash should be left behind. Sugar suffers 
perhaps more than anything else by exposure to 
air and dust — from the air it absorbs moisture 
and dust accumulates on the surface. 

Never buy a dirty sample, never buy a moist 
one. Water is of course sometimes added to 
increase weight. Pure sugar crystals should have 
a specific gravity of 1*606, and are soluble in one- 
third of their weight in cold water, and even more 
so in hot water, while at boiling you get a syrupy 

If you suspect sugar of having been damped 
for the sake of increasing weight, take a weighed 
half- ounce, put it in something, and slowly dry it 
for an hour ; after that time weigh it again, if it 
has lost weight of course it is due to moisture; 
stand it aside for another drying, then give it 
another weighing ; repeat the operation till it does 
not alter in its weight. You can then compare 
the weights at the commencement and at the finish 
of the operation. The drying temperature must 
not be much above the ordinary air temperature. 

Treacle. — This is the uncrystallizable part of the 
sugar, and only that from cane-sugar ought to be 
used. That from beet-sugar is offensive both in 
smell and taste. This is due to the salts and 
flavouring matter which naturally belong to beet- 
root syrup. These cannot be got rid of; it is, 
therefore, impossible to get an agreeable smelling 


sample, or one that can be used with comfort as 
an edible accompaniment to other food. 

We believe that beet-root treacle is always 
condemned by the Inland Revenue, under the 
Food and Drugs Act, for use in the Government 
departments. Real golden syrup is good, do not 
buy any other, for the inferior treacles are made 

Fig. 32.— Crystals of Cane-sugar. 

up of all kinds of vile material. In Fig. 32 we 
give a microscopic sketch of cane-sugar. 

Confectionery and sweetmeats. — These we have 
now in great purity, while a few years ago we 
could not have said so. Many of the stiff icings 
were made of chalk, flour, plaster of Paris, and 
were coloured with all sorts of poisonous substances. 
The aim was to please the eye, the poisoning 
qualities of the colours did not seem to be taken 


into consideration. Now all this is altered, and 
we may certainly thank the Adulterations Act 
for it. 

Confections and icings and children's sweets 
are now for the most part made of sugar only, and 
the bright tints are produced from various coal- 
tar colours, or the aniline dyes, as they are some- 
times called. From the use of these you can get 
the brightest tints, without using sufficient to 
appreciably increase the weight or affect the 

To test sweets of any kind — sugar sweets we 
refer to here, for chocolate sweets, of which so 
many and beautiful varieties are in the market, and 
which are so much " loved " by the children, are to 
be tested by methods already pointed out — break 
them up in a mortar (a small quantity only need 
be taken), dissolve the powder in cold water : if all 
is dissolved, nothing but pure sugar is present; if 
the solution is coloured, it is probably derived 
from the source we have already mentioned ; 
should there be a sediment, filter it off, dry the 
powder or sediment ; if it be coloured, examine it 
by rubbing it between the fingers, and notice 
whether it is tough or brittle, whether the colour 
is derived from the powder being stained, or 
whether the powder itself is the colour-producer; 
if so, it is probably derived from a metallic source, 
and should be suspected. Take a portion of the 
sediment, put under the microscope and examine 
it; this examination should confirm this point. To 


discover what the mineral is requires more tests 
than we can give here. Supposing, however, it is 
starch or flour, you will be able to tell at once by 
the microscope. Buy only the pure high-class 
sweets, avoid any that look to be made of "■stuffs." 
Those made of gums and gelatines can be dissolved 
although not easy to pound, and can be dealt with 
as we have already mentioned. 

We cannot help adding here a caution in 
reference to the cheap ices sold by various vendors 
who perambulate the streets of London and large 
towns with such sweets on barrows. These con- 
coctions of ices are generally of the vilest kind 
and often injurious to health, yet they form such 
temptations to young folks, that the barrow of the 
vendor forms a favourite lounge for them. 

A medical officer of health made it his special 
business to inquire into the composition of these 
" delicately-flavoured " ices. He found the com- 
pound to consist of flour, milk, eggs, and flavouring 
essences, and countless microbes, one deadly speci- 
men of which is commonly found in sewage. 

No wonder we often hear of children being ill, 
and sometimes poisoned to death after indulging 
in such horrible mixtures. The water in which 
the glasses themselves are washed is filthy, and 
the preparation of the u ice-cream " is carried on 
by individuals who have no notion of cleanly 
habits, or of using clean vessels in the preparation 
of their wares. 

Honey. — The tempting little squares of honey, 


"even in the honeycomb," are unfortunately 
adulterated, and do not always consist of honey 
pure and simple, and is frequently such as the 
"busy bee" would not own as any of her make. 
The cell walls are made of solid paraffin, and the 
cells themselves often filled with sugar-syrup, 
glucose, to which a little honey is added to carry 
out the deceit a little more surely by giving it a 
flavour. That sold in jars suffers in the same way. 
This is one of the disadvantages of the advance- 
ment of chemistry. The glucose is made by the 
action of sulphuric acid on potato starch. Potato 
starch again, you will say ! Yes, we owe a good 
deal to this humble vegetable, the potato. Who 
would have discovered its virtues if Raleigh had 

It is difficult to find a simple test for this fraud, 
except a drop of sulphuric acid — it will at once 
blacken and char true bee's-wax, but will not 
touch paraffin. The sugar is not the same as 
cane sugar, for honey sugar is glucose, the same 
substance chemically as that made from potato 
starch. The microscope is the only aid we can 
recommend in this case. A thorough familiarity 
with the appearance of natural honey should be 
of service in examining any sample you may buy. 
In Fig. 33 we give a sketch of honey under the 
microscope — seeds, hairs, and other items obtained 
from plants will show up in such case, which in 
an artificially prepared sample would be wanting. 

Jams. — Here we open up a big subject, and 


yet a very common one. We all know how jams 
are appreciated by the children, and that they 
like "real jam." We generally understand this 
to mean ripe, good sound fruit, boiled down with 
pure cane sugar. Such jam will retain the taste 
of the fruit, and if the boiling has been carefully 
done, and the jars securely covered, and they are 

Fig. 33.— Genuine Honey. 

stored in a dry place, they will remain good for 
several years. 

Most of the jam sent into the market is pure 
and good, much more than formerly; at the 
same time, if we keep to our definition that 
jam should only consist of fruit and sugar, no 
substance is more given to adulteration than jam. 
So many tasteless vegetables, like marrows, 
pumpkins, and turnips, are cut up and put with 
almost any fruit, and they take the flavour. The 


rt mixed jams," the breakfast jams, and others, are 
many of them disreputable concoctions, and if 
they were not sweet and sticky would not be 
liked even by the most innocent tasters of real 
" raspberry." The jams of the best and purest 
kinds are put up in jars of largest capacities, and 
by firms of the highest repute, but that sold in 
small quantities of pennyworths and less in our 
poorer neighbourhoods is vile stuff. 

To examine a jam, you must know what fruit 
to look for, and find out the cane sugar. Some 
very thin sections of fruit may be looked at under 
the microscope, and by that means cane sugar 
may be detected. By washing a little; however, 
and making a thin solution of the juice, you can 
perhaps tell without this; it is the pulp that 
must be examined, the fibres, the seeds ; for 
"raspberry" jam, so called, is often made no\v-a- 
days without any such fruit coming into it. 

The same remarks apply to marmalades. The 

t fruit must be thoroughly looked at; portions of 
the pulp and rind can be examined by the 
To many, jam is but a * sweet squash," for not 
very long ago we witnessed a transaction which 
told this very plainly. An individual was buying 
a glass jar of strawberry jam : a very good sample 
was shown him, in which the strawberries were 
whole — had not been boiled to a mash. That, 
however, did not suit the customer. He wanted 
a jam where all the fruit was so crushed that it 


was impossible to distinguish what fruit was 
employed. This kind of jam was at once supplied 
to him. 

Buy the best jams, made by the best makers, 
or what is better still, if you have the convenience, 
" make them at home." They cost a trifle more, 
but you know what they consist of, and no 
conserve beats a good home-made jam. 




Vinegar. — Good malt vinegar is the best to 
employ for pickling and for general table use. 
Its preparation in the early processes is very 
much like that of brewing. The adulterations 
to which it is subjected, and the substitutions for 
it, often cause failures with pickles and other 
preparations requiring a good vinegar. Crude 
acetic acid is often used instead of vinegar in 
putting up common pickles, and that supplied at 
low-classed oyster-stalls is often but a mere 
concoction of dilute sulphuric acid coloured with 
a little burnt sugar. Pungency is no proof of a 
vinegar being good, but rather of the contrary — of 
one to be suspected. Sometimes pungency is 
brought about by the addition of sulphuric acid, 
by chillies, cayenne pepper, or grains of paradise. 
The latter substances are rather difficult to detect, 
but not so the former. Make a solution of halt' 
water and half vinegar, of two table-spoonfuls of 


each, add two or three drops of aniline violet: no 
change of colour will result if no sulphuric or 
other mineral acid be present. The presence of 
these acids to the extent of 0*2 per cent, will 
change the liquid to a blue tint. The presence of 
05 per cent, of mineral acids will give a blue- 
green tint, and 1 per cent, of acid will change it 
to a bright green. This aniline violet is a very 
delicate test for the presence of sulphuric acid. 

When there was a duty on vinegar, one part 
per thousand of sulphuric acid was allowed to be 
put with vinegar with the idea of keeping it, 
owing to the "ropiness," or fermentation, that 
is likely to take place in it, and which would 
decompose the acetic acid of the vinegar. Another 
test may be given for detecting sulphuric acid. 
Take a little solution of barium chloride, drop it 
into a mixture of the vinegar and water, it will 
cause a white precipitate, which if it quickly 
falls add more; should this precipitate be much 
repeated, you may be sure that more than the legal 
quantity of sulphuric acid has been added. 

To take the specific gravity of vinegar is another 
good test of its quality. Taking water at 1000, 
vinegar should weigh 1015 ; anything less than 
this is to be suspected. Water and sulphuric 
acid are the principal adulterants for vinegar, and 
both can be detected by these methods. Avoid 
cheap vinegars, very pungent and very weak 

In making home-made pickles, your vegetables 


will only keep well and do well by being put up 
in good vinegar. Good malt vinegar, both brown 
and white, may be obtained for this purpose. 

Pickles. — Good pickles should contain sound, 
fresh vegetables, put up with genuine spices, in 
good malt vinegar. Formerly, much more than 
now,metallic salts were added to give the vegetables 
a fine green appearance. This to a great extent 
is now discontinued. The bright green colour was 
due to a copper salt. It could, however, be detected 
by putting in a clean knife ; it at once became 
coated with metallic copper of a bright-red hue. 
Pickles at present put up by good makers are 
thoroughly reliable, but some put up for "immediate 
use," which are sold in poor neighbourhoods by 
the " pen'rlorth,' , are vile enough, and sure enough 
to produce indigestion. The vegetables, not the 
best nor the most carefully prepared, are put into 
a salt brine, lying there for perhaps two days, 
brought out, then put into a mixture of crude 
acid coloured and thickened by turmeric, mustard, 
and starch, with a few spices, and sent out to be sold 
and eaten next day. The best pickles are prepared 
carefully, and not put into the market till the} 
are ready to be eaten. 

The very inferiority of the mixture we have 
described constitutes adulteration in the com- 
monest kind of pickles. They cannot be eaten 
with impunity. An examination of the vegetables 
will enable you to detect whether all is stalk or 
the inferior portions, and if they are old or 


damaged ; this may to some extent be discovered 
on eating them. 

Turmeric and substances used in making picca- 
lilli may be discovered on drying up some of the 
mixture, then breaking it up, and using the 
microscope; any starch will at once be detected. 
Flavour, crispness, and the kind of piquancy 

Fig. 34. — Double-superfine Mustard. 

apart from pungency, distinguishes a good pickle 
from a common or an adulterated aiticle. 

These remarks apply chiefly to the pickles of a 
mixed character, a pickle consisting of one kind 
of vegetable only — such as cabbage, onions, wal- 
nuts, &c. — must be judged on similar merits. Thin 
slices of vegetables can be examined by the 


Mustard. — This substance is adulterated to an 

enormous extent. In a loose sample you would 
rarely get it pure. In tins prepared by makers 
of repute you may depend on having it according 
to the guarantee on the label of each tin. A 
plea is often made that pure mustard does not 
mix well for table purposes. This is not true. It 

Fig. 35. — Pure Mustard. 

does not keep quite so long perhaps; but that 
difficulty would be overcome if a less quantity 
were mixed at one time. Mustard is a much 
more enjoyable condiment when pure. In Fig. 34 
we give a microscopic sketch of the so-called 
" double superfine" mustard. You notice that 
the mustard seeds, a a, contain oil-bearing cells ; 
it is from these the flavour is derived, b b are 
starch granules of wheaten flour ; c c are cells of 


turmeric powder. The mustard-cells look some- 
thing like starch confined in skins (Fig. 35) ; but 
these husks really consist of three membranes, 
and are hexagonal in shape. To see this perfectly 
in a genuine specimen, break up a mustard seed 
and examine it for your standard of comparison. 
If these cells are dropped into water they swell up ; 
if you add iodine tincture to this you get no change 
of colour. 

The substances with which mustard is largely 
adulterated are flour, turmeric, various starches, 
yellow dye stuff, and even ginger and cayenne 
pepper. The best test for starch we have already 
given is the iodine tincture ; for turmeric use a 
little ammonia, which at once turns it brown. 
The microscope is the best help of all, for you can 
see not only the substances present, but their 
proportions. Pure mustard costs about 2s. per 
pound, its adulterants only a trifle of that cost. 
Mustard being frequently employed medicinally 
for plasters, has its strength materially interfered 
with when adulterated with starch to any great 
extent. This difficulty is got over by using 
mustard leaves, consisting of thin diaphragms 
covered with mustard flour only, which are speci- 
ally prepared for this purpose. 

The Commercial View of Mustard. 

The following paragraph from a pamphlet by 
Messrs. J. & J. Colman on the preparation and 


public appreciation of this condiment is so inter- 
esting that we quote it in full. 

" Mustard of commerce or table mustard is one of 
those articles which has given rise to considerable 
discussion under the Adulteration of Food and 
Drugs Act, 1872. On the one hand it has been 
contended that pure flour of mustard only should 
be sold to the public. This view has been strongly 
advocated by prominent food analysts; while, on 
the other hand, men occupying equally high 
scientific positions see no reason to object to mix- 
tures of mustard flour with suitable proportions of 
wheaten or rice flour, to moderate the somewhat 
coarse and bitter flavour of pure mustard, and to 
assist in preserving the article from decomposition, 
both in the dry and wet form, since perfectly pure 
mustard is very prone to undergo a change by 
variation of temperature and exposure to air, 
which by no means adds to its value as a condi- 
ment, in fact, renders it offensive. 

" The practice adopted by the largest mustard 
makers, is to prepare mustards of three or four 
grades to suit the tastes and pockets of the public. 
One set of these mustards is perfectly pure, and 
the other set are mixed mustards, commonly 
called mustard condiments. Both sets are sold at 
precisely the same prices, and they are calculated 
to yield the same profits to the makers. The 
justification for the use of mixtures here is that 
the finest quality of seed is used, and by tempering 
this with a small proportion of wheaten flour they 


are able to produce a table mustard which shall 
possess the finest aroma and pungency, and which 
will keep much better, and be free from the bitter- 
ness and coarseness of flavour common to pure 
mustard. That the public taste approves this is 
manifest by the preponderance in the sale of the 
condiment mustard over that of the pure." 

Spices.— These are generally adulterated with 
inferior substances belonging to the class they 
represent, or with fibre and absorbent substances 
steeped in oils imitating the flavour of genuine 
spice, and with partially spent samples. 

Pepper. — Ground pepper often consists of dust, 
sand, rice-flour, sago-flour, and other substances, 
with a portion of genuine pepper. In addition to 
these, ground pepper leaves, mustard, rape seed, 
burnt bread, and bone-dust have been discovered. 
How nice a condiment is P.D. (pepper dust). The 
microscope helps us here again in the discovery of 
adulteration. We must, however, have a genuine 
peppercorn to begin with, and surely we can find 
one. Crush it up, and it should yield a powder 
which, on being examined with the microscope, 
should look like Fig. 36. You may say, " I get 
over this difficulty by buying my pepper whole ; " 
but manufactured peppercorns are put into the 
market, made of bran, clay, chicory, oil-cake, fla- 
voured with pepper oil and cayenne pepper. So that 
the microscope is the only ready means we can 
recommend for the easy detection of these things. 

Nutmegs, cloves, and ginger. — The former of 


these are sometimes artificially produced, and 
flavoured with nutmeg oil. The cloves are often 
the spent spice dried and done up again, with 
some genuine oil of cloves put to them, just suf- 
ficient to pass them off, or they may be an old 
and damaged stock. Ginger is often made of 

Fig. 30.— Crushed Pepper-corn. 

spent samples, made pungent by various oils. 

The detection of adulteration in these is trouble- 
some, and must be tested by grating a small 
quantity of each, and dropping it into cold water ; 
if it floats it may be a genuine good substance, 
but even then we cannot be quite sure. Only 
good spices should be used in making pickles. 

With other spices, as with the two last, we can 
only recommend the microscope as the reliable 



guide, after taking a known genuine specimen as 
the standard of comparison. 

Olive oil. — This oil, which goes by the name of 
salad oil, has been so prominently before the public 
lately, that we are now quite convinced that very 
much that is sold is not the product of the olive 
at all. We are further informed, that not enough 
olives are grown to produce the amount of oil 
required for the market. The term salad oil is 
applied to it so that the seller of the sample sold 
under that title gets out of the difficulty of giving 
a guarantee that it is olive oil. 

Genuine olive oil is clear, of a pale yellow 
tinge, and becomes solid at a temperature of 
about 44»° F. So many other oils resemble it, 
that at sight we should probably be unable to dis- 
tinguish whether we had a mixed sample, or even 
one where not a particle of olive oil was present. 
If we look at the specific gravity of those oils that 
are substituted for it, or mixed with it, they run 
so close together that it is not much of a guide for 
us. The following table gives the specific gravity 
at 59° F., taking water at T000. 

Olive oil (genuine) 


Poppy oil 


Cotton seed oil 


Sweet almond 


Colza oil 


Nut oil 


Beech-nut oil 


The test that seems easiest for pure olive oil, is 
to take one part of strong nitric acid and nine 


parts of oil, put them together in a test-tube, 
warm them till action is fairly set up, then remove 
the flame. Intimately mix them, then the pure 
oil will set in a hard mass of a pale straw colour, 
while all other oils will have a higher tint. 

The writer of an article on " Olive-oil making 
near Florence" in Good Words for June, 1895, 
remarks : " Scarcely has it (the oil) left the hands 
of the peasants before it is manipulated and 
adulterated to such an extent that even in Flor- 
ence pure olive-oil is almost unobtainable. The 
Italian Government has offered prizes for the dis- 
covery of a method of exposing the adulteration." 




Beers. — England has always been famed for its 
beers. Before the introduction of tea into Eng- 
land, beer and mead seem to have been the drinks 
of the people. Tea and coffee are the beverages 
now that we like hot, beer is preferred cold. 

Pure beers consist of malt and hops, and when 
these only are used, an agreeable, wholesome 
drink is the result. 

It is said that beers are much adulterated, but 
beyond the dilution with water, we do not think 
this is the case. The substitutes of sugar solu- 
tions and saccharine for malt is not at present 
considered an adulteration, although we think it 
should be classed as such. 

Beers, of course, vary in their strength, some 
contain as much as 9 per cent, of alcohol, while 
small beers contain as little as 2 per cent. 

A sound light beer is a great desideratum, for 
an English workman has an idea that he must 


have his beer. He does his work better with than 
without it, it quenches thirst, and on the score of 
cheapness it can be sold cheaper than any other 
drink, unless it is cold water. A pure light beer 
would also do much to promote the cause of 

The convictions for adulteration that have 
lately come under our notice have been for the 
addition of water and sugar, and some few months 
ago these cases were rather numerous. These 
additions lessen the tonic properties of the beer 
and dilute its strength. Till a standard specific 
gravity is imposed on beer, it is difficult to judge 
how far beer has been adulterated. 

Salt is sometimes used in adulterating beers, 
and certain mixtures called "heading powders" 
are made use of to enable publicans to bring the 
beer up, to give it a " frothy head." 

Salicylic acid, as we have been told, is some- 
times used ; this may have been added to a slight 
extent with the idea of preserving the beer. 

Customers are in a great measure to blame for 
many of these adulterations — for some want a 
bitter beer, some a sweet beer, some a light beer, 
others a dark brown — all these can be supplied 
from the same stock, with slight additions to briiiir 
about these several results. If a beer leaves a 
very bitter taste in the mouth, and this taste 
lasts for some time, there is no doubt that the 
bitterness is not due to hops only, but sonic 
adulterant has been added to secure this bitterness. 


The analysis of beer is rather a troublesome 
one, so that, with the exception of one or two tests, 
we shall not pursue this subject. 

The "smack of age" in some beers may be due 
to the presence of sulphuric acid. To be sure of 
this, take a small quantity of the beer, add to it a 
little distilled water, or some water that has been 
well boiled. Then add a few drops of chloride of 
barium solution — if the mixture is cloudy it may 
be due to sulphuric acid, but all beers contain 
more or less of the sulphates of lime and magnesia 
derived from the water used in brewing. 

To test the presence of ordinary salt, take a 
second quantity of the beer, add a drop or two of 
nitrate of silver solution. If the mixture becomes 
thick and cloudy salt may have been added. 

The quantity of alcohol in beer may be ascer- 
tained by the process of distilling a small portion 
in a retort ; collect the distillate, add to it enough 
distilled water to bring its quantity up to that of 
the beer in the first place used. Then take the 
specific gravity of the liquid. In referring this to 
the table in the Appendix, you will find the 
quantity of spirit represented by that specific 

To ascertain the quantity of extract, take 100 
grains by weight, in a very light saucer or porce- 
lain dish — having weighed the saucer before using 
it — then evaporate the liquid, and weigh it again 
with all that is left in the saucer. 

The best way to avoid adulteration is to buy 


good quality beer from a good brewer, either in 
cask or bottle. 

Wines. — The wines called port and sherry are 
made stronger or "fortified" by the addition of 
spirits before they come to this country at all. 
Many of the lower-priced wines are heightened in 
colour and strength by fictitious means, while 
some are probably mixtures of flavours and 
essences, coloured, to which common spirit is 
added, without having any acquaintance what- 
ever with the juice of the grape. Our best wines, 
in fact, all bought for a fair price at respectable 
merchants, are fairly pure. 

Home-made wines and many British wines are 
wholesome and refreshing beverages, and are 
generally free from adulteration. The colouring 
matter of wines is often from the juice of elder- 
berries, blackberries, and even bilberries, but 
logwood, cochineal, and such substances, are only 
used for the mixtures of the lowest descriptions 
passed off as wines. 

To ascertain the quantity of alcohol in wine, 
pursue much the same method as that recom- 
mended for beers, only that at least two-thirds 
of the bulk of the wine taken should be distilled 
over, then the quantity made up to the original 
bulk with distilled water. Take the specific 
gravity, and refer to the table for percentage of 
spirits. Beyond this the amateur can scarcely 
go, for colouring matter and essences require 


careful analysis to determine the source from 
which they come. 

The light wines, like the clarets, should contain 
nothing but the juice of the grape; such are 
among the most wholesome of the alcoholic bever- 
ages. Their percentage of alcohol is low. 

Spirits. — Brandy : this is a delicate spirit when 
pure, and is the best for medicinal purposes. It 
is prepared by distilling wine. Unfortunately, 
however, it so often consists of inferior spirits — 
such as may be distilled from potato mash, 
coloured with burnt sugar, and flavoured more or 
less with genuine brandy. Such a spirit may at 
once be detected by the harsh burning sensation 
produced on the palate. Various recipes for mak- 
ing British brandy are amusing, because they show 
how very little of the real article they contain. 

Whisky, gin, and other spirits are largely 
made in England. The great adulterant is water ; 
and another great evil exists, they are put into the 
market for sale and consumption when they are 
much too new, and thus they get the reputation of 
being largely adulterated. Spirits, especially when 
new, are contaminated with fusel oil, which has a 
very nauseous taste and fiery flavour, and also 
acts most injuriously on persons drinking such 
spirits. It is one of those substances that can 
hardly be got rid of by distillation, and only 
disappears by age. 

The presence of this substance may be recog- 


nized by the smell. Allow a few drops of the 
suspected spirit to evaporate from the hand, or 
rub a few drops between the hands, the pungency 
of the smell may be taken as an indication of the 
quantity present. 

Another test is to add a few drops of nitrate of 
silver to a small quantity of the spirit. Place the 
mixture in the sunshine : if a red tinge develops 
fusel oil is present, if no change in colour takes 
place in the mixture this substance is absent. 
Retailers bring down the strength of spirits con- 
siderably by the addition of water. By taking the 
specific gravity of the liquid you can ascertain 
the quantity of alcohol they contain by methods 
already pointed out. 

Spirits are always compared with a standard 
called " proof-spirit," which consists of 49'37 per 
cent, of absolute alcohol and 50'63 per cent, of 
pure water. Absolute alcohol has a specific 
gravity of 0'7398, and proof-spirit has a specific 
gravity of - 9198. In the sale of spirits they are 
quoted at so much "over-proof" or "under-proof." 
(See Table I. in Appendix.) 

Rum is prepared by distilling molasses, its 
e:>pecial flavour being derived from an oil in the 
molasses. Gin derives its flavour from juniper 
berries, sweet flag, and other vegetable flavouring 
matters. It has been said that sulphuric acid is 
added to spirits to increase their pungency, but 
the flavour of this acid is too pronounced for such 
a purpose. The test for this is chloride of barium, 


as we have already pointed out (p. 90), and tins can 
easily be applied if this substance is suspected at 

Aerated drinks. — These are extensively used 
now-a-days, and are sold in strong corked and stop- 
pered bottles, also in " syphons." Many of them 
are said to contain salts of various kinds, but they 
ought also to have a label attached telling the 
quantity of the salt per pint or per cent. They 
should contain carbonic acid gas, but many contain 
merely compressed air, and may be distinguished 
by its bubbling away rapidly, leaving the water 
flat to the taste. The simple aerated water — dis- 
tilled if possible — is best for general purposes, 1 the 
various salts present being of a medicinal char- 
acter. Lemonade and ginger-beer come under 
this heading, and are merely aerated drinks 
flavoured with lemon or ginger. 

The various essences and substances sold for 
flavouring and for making sparkling summer drinks 
should always be used with caution, they being 
as a rule mere concoctions, which one is better 

Lime-juice. — Among the most frequent drinks 
in summer is that from the juice of the lime-fruit. 
When pure this is very good — it, however, so 
frequently receives its sharpness from sulphuric 
acid. The test for this substance we have given 

1 The source of water supply for these drinks is im- 
portant. It is best to have distilled water, such as that 
supplied by the Pure Water Company, Battersea Park, S.W. 


previously. Effervescing drinks, made by mixing 
some acid, like tartaric or citric, with a quantity 
of an alkali to neutralize it, are often used in the 
summer-time. These should be taken sparingly, 
for if constantly used they are very liable to pro- 
duce indigestion. The so-called "nerve tonics" 
also must be taken very cautiously, for many of 
them are more pernicious than even alcohol. 

Home-made ginger-beer, and the refreshing 
lemonade made by slicing lemons, pouring on hot 
water, and adding sugar, then diluting with cold 
water, make agreeable and refreshing drinks, and 
may be taken without any fear of adulterations. 




In our former chapters we have had it im- 
pressed on us that we should be careful to have 
our food as pure as we can get it. At the same 
time, it is even more important that the air we 
breathe and the water we drink should be in the 
fittest conditions for promoting and sustaining 
healthy life. These two points are so often lost 
sight of, that both are frequently contaminated 
from mere carelessness. 

The air in the country, *. c. away from the town, 
is so fresh and nice, and sometimes so bracing, 
yet houses in these healthy spots are frequently so 
badly ventilated, that the rooms appear close and 
stuffy. We cannot here give a paragraph on 
ventilation, but can only say, with much emphasis, 
that every room in a house should have a means 


for the breathed air to escape, and for fresh air to 
find its way in. This should be the case espe- 
cially with our sleeping-rooms. 

A very good test, and one that is very easy to 
carry out, is to take a pint bottle full of water 
into a room, and then let the water run out, of 
course the air will at once replace the water. Put 
into this bottle one ounce of lime-water, shake it 
up ; if the lime-water remains clear after this 
shaking, the air in the bottle contains less than 
six parts of carbonic acid to the 10,000 ; should 
any turbidity show itself, more carbonic acid is 
present than there ought to be. We mentioned 
sleeping-rooms specially, because it is here we 
spend nearly one-third of our lives. Do not let 
us put up with adulterated air, any more than 
with adulterated bread and butter. 

Water as supplied by the great water-com- 
panies to most towns is generally sufficiently 
good to be above suspicion. In the summer-time, 
however, it is well not to be too sure of this. 

A good filter is an excellent thing to have at 
hand. If, however, this is a charcoal filter, do not 
let the charcoal be in use too long without clean- 
ing it, either by scrubbing it or by baking it. A 
serviceable filter can be made for a few pence. 
Take a flower-pot, fix a piece of sponge to block 
up the hole, then put a layer of magnetic oxide of 
iron or polarite, which can be bought for one penny 
per pound, cover this with a layer of sand. If 
in the case of very foul water, let the water first 


be boiled, and then run through the filter, — it will 
run through, practically speaking, pure. 

Soft-water should not be stored in leaden-lined 
cisterns, and cisterns of all kinds in which we 
store drinking-water should be kept clean. Even 
in many of our model dwellings this is a point 
frequently over-looked. They should be securely 
covered ; no drain-pipe, or pipe conveying sewer- 
gas, should have access to water-cisterns. We 
frequently find people who are scrupulously clean 
in other matters careless of this most important 
one, keeping the cistern for the drinking supply 
thoroughly clean. Medical officers of health and 
sanitary inspectors' reports often tell very serious 
stories about the condition in which they find 
these water stores. In so bad a condition are 
some, that it is a wonder the families using them 
are not oftener ill than they are. 

Boiled water is rather disagreeable for drinking 
purposes, but it is agreeably aerated if after 
boiling it is run through a charcoal filter. This 
may be effected by using another flower-pot, and 
covering the bottom with a thick layer of freshly- 
prepared charcoal. 

Very hard waters should be boiled before being 
used, hardness in such a case being reduced by 
the precipitation of the lime. Hardness in water 
may readily be detected by its refusal to form a 
lather with soap. Hard-water is not therefore 
economical for laundry purposes. 

The following are two useful tests for organic 


impurities in water — impurities which should be 
guarded against — 

1. To a portion of the water, either in a test- 
tube or in a wine-glass, put a few drops of solution 
of nitrate of silver; a white precipitate will 
indicate the presence of chlorides. This pre- 
cipitate is readily soluble in liquid ammonia. 

2. Take half-a-pint of water, put in a few 
drops of sulphuric acid, then add a small quantity 
of the solution of permanganate of potash (Condy's 
fluid). The solution will then be a bright pink ; 
should this disappear after a short time, you may 
be sure the water contains some sewage matter or 
other organic impurity. Drinking-water convicted 
by either of these tests must be abandoned till 
the evil is remedied. 

Preserved and mixed food. — We cannot close 
this chapter without a few words on the care 
which should always be exercised when purchasing 
food. In buying fresh meat, be careful that it 
does not come in contact with anything that may 
convey a taste to it; notice that the lean is a 
healthy-looking red — no sickliness about it, that 
the fat is not too white or too yellow, that there 
is no flabbiness about it. In buying bacon, and 
salted or dried meats, notice that everything about 
it is clean, fat not yellow, no rancid smell about it, 
and that by the bone it is quite sweet. 

In buying sausages and mixed meats — which 
are sometimes marvellous masses of mystery — be 


exceedingly careful. To show what we mean, we 
give the analysis of a sample of sausages brought 
into a police-court not long ago. 
The sample consisted of — 

Brown bread, 


Flesh, meat, seasoning. 

10 >TTF 

ing, tV J 

German sausage, brawn, and mixed meats of 
this kind, are so very liable to adulteration that it 
is well to know the responsible person from whom 
these things are supplied to be sure that they are 
genuine. If you take a small portion for examin- 
ation, you will be able to tell whether you have 
meat or bread-crumbs, and whether they are good. 
The microscope will also help you to determine the 
kind of spices employed as well as the quantity. 
In buying tinned meats and preparations, never 
choose those where the ends of the tins bulge out, 
but always those that give a good hollow at the 
ends. These show that the air has been well 
driven out from the contents of the tin, which will 
be found sound and good. Never buy soiled eat- 
ables of any description. 

In buying fish, freshness is the great secret of 
its being good, and not liable to disagree with the 
eater. Rely on your own judgment in selecting 
fish, in point of freshness, — the appearance of the 
eyes and gills will tell you, — and never buy any 
if the scales show the least phosphorescence. 

In selecting vegetables, again, freshness has 


much to do with their goodness; bruised and 
battered fruit are not good, unripe or unsound 
fruit should be avoided. In washing vegetables 
and salads, let the water be wholesome and fresh, 
and use plenty of it. We are just reminded of 
the scare which took place a little time ago, 
where the spread of typhoid fever was put down 
to the eating of water-cress which had grown 
on land watered with sewage-water. Had the 
salad been thoroughly and carefully washed, no 
such thing could have arisen, for whatever carried 
the mischief was on the outside. All such cases 
as this are adulteration arising from negligence 
in one's own home. Cleanliness is the weapon 
that baffles most disease. 



Table for calculating the quantity of absolute 
alcohol in a liquid, from taking its specific 
gravity at 60° F., and estimating from the same 
how much such a liquid is over or under proof 

Proof-spirit, as given on p. 105, consists of 49'37 
of pure alcohol, with 5063 per cent, of distilled 
water. This mixture has a specific gravity of 
0*9198, in other words it is Jf the weight of 
water, i.e. 12 vols, of water should exactly balance 
13 vols, of proof-spirit. 

Specific gravity 

Percentage of 

Per cent. U. P. 

of liquid. 











95 4 










































Specific gravity 

Percentage of 

Per cent. U. P. 

of liquid. 











26 6 







O. P. (over-proof). 



















In this table the specific gravity of the liquid is 
given to four decimal places. In the experiment 
with specific gravity bottle we only work to three 
decimal places. An average, therefore, must be 
taken, as must also be the case where an inter- 
mediate specific gravity is not given in the table. 
In using the table the distillates mentioned must 
only be used, for if a liquid such as a wine or 
a cordial spirit is taken, its specific gravity is 
increased by sugar and other substances present, 
to which the flavour of the liquid is due. Where 
a spirit such as whisky, gin, or a cordial has to 
be tested, the distillation must be conducted at a 
low temperature, and great care taken so as not 
to allow the escape of the volatile spirit. The 
amount of sugar and other extracts can be ascer- 
tained by taking a weighed quantity in a dish 
and after weighing, slowly evaporate the liquid 
till only the extract is left, then weigh it, and 
compare it with the original weight of the sub- 
stance taken, and then find the percentage by 
ordinary arithmetic. 



In taking a temperature with a thermometer 
graduated according to Fahrenheit's scale, marked 
Fah. or simply F., it is often required to convert 
the same into a Centigrade reading marked Cent. 
or simply C, and vice versa. 

The following simple rules will be of assistance 
to those who are not already acquainted with the 
method of changing the readings from one to the 
other. In making a comparison of the readings 
it is necessary to remember that boiling-point, 
marked B.P. Fah., is 212°, and B.P. Cent, is 100°; 
freezing-point, marked F.P. Fah., is 32°, and F.P. 
Cent, is 0° or zero. 

Between freezing-point and boiling-point Fah. 
there are 180° ; between F.P. and B.P. Cent, are 

Each division, called a degree, marked ° Fah. = 
iU or V C, and each ° C = f° Fah. 

Then apply the following rules. 

1. To reduce a Fah. reading to C. subtract 32 
and multiply the remainder by f . E. g. To reduce 
104° Fah. to a C. reading- 
Subtract 32, i. e. 104-32 = 72. 


Multiply by f = 7J £ f, = 40. 

.'. 40° C. is the same temperature as 104° 

2. To reduce a C. reading to Fab. Multiply 
by {t then add 32. E. g. To reduce 75° C. to 

Multiply by f = 7 -^ 9 = 135. 

Add 32 = 135 + 32 = 167. 

/. 167° Fah. is the same as 75° C. 


List of apparatus and chemical tests recom- 
mended in the methods for detecting the various 


Magnifying-glass. 250 grs. specific gravity bottle. 

Microscope. Chemical thermometer to 

Lactometer. 240° F. 

Creamometer. Set of 3 beakers. 

Pestle and mortar. Tin saucer, 3" in diameter. 

Two nests of 6 test-tubes each. 

Small set of Apothecaries' scales and weights. 


Tincture of iodine. Solution: Aniline violet. 
Solution: Logwood. „ Ferrocyanide potass. 

„ Car. ammonia. „ Permanganate „ 

Liquid ammonia. Sulphuric acid. 

Solution : Nitrate of silver. Nitric acid. 

„ Barium chloride. Hydrochloric acid. 
Methylated spirit. Litmus test-papers, blue and red, 
and turmeric papers. 


Readers can obtain the materials of any good 
druggist, and prepare all these solutions them- 
selves from the instructions given, but for the 
sake of those living away from London or large 
towns we give the following information. Sets of 
tests already prepared — with or without apparatus 
— may be had of Messrs. Townson and Mercer, 89 
Bishopsgate Street, E.C., Messrs. Orme, 65 Bar- 
bican, E.C., or of Messrs. J. & J. Griffin, Garrick 
Street, W.C., who will also supply microscopes. 
Messrs. Townson and Mercer supply an excellent 
Educational microscope in case for £2 2s., which 
is powerful enough to distinguish the various 
starches, while Messrs. Gregory, of 51 Strand, 
W.C., supply a pretty little instrument for 17s. (yd., 
which will just distinguish the starches, but for 
the more elaborate instruments the reader cannot 
do better than write to the firms already named, 
describing their wants, or to Messrs. Newton & 
Co., 3 Fleet Street, E.C., Messrs. Ross, 111 New 
Bond Street, W., or some other celebrated makers 
of optical instruments, who will give any informa- 
tion on the qualities of their various instruments, 
ranging in price from three guineas to one hun- 
dred guineas. 

The patentee of the Tell-tale Milk-jug figured 
on page 50 is Mr. J. Lawrence, 56 Fulham Road, 
London, S.W. 

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Simple Experiments for Science Teaching. Includ- 
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